Well,

"IF" this occurs again and I expect it will, I will start attempting to diag any possible issue you guys can come up with that I haven't thought of. I do believe I once again received a bad ECM. The last 4 were from China, this one was from Mexico. I just ordered another one from Mexico. I found by accident that when you pushed down on certain areas of the board inside the MIL light and fans would come on and then when you released they would sound like they were shorting. Even with one person pushing down and me trying to make communication with the vehicle we weren't able to accomplish our goal. So I took it back to the auto parts store, accompanied by a video this time and they ordered me yet another one.

I have two questions at this particular moment.

1. Does anyone have a list of vehicles/and or part numbers of ECM's that will work with this car. I am thinking of heading to the U Pull it yard for an off model donor

2. Is anyone willing to sell a known good ECM that will work with this vehicle. If I can get a hold of an honest known good ECM i can put all this to bed and start focusing on the car again..... or it will just run and ill be happy. Either way works,

Dan

Picked up the new ECM this morning. No good news. After fiddling with Tuner Pro for 2 hours I went back to my trusty scan tool only to find the vehicle is not communicating with the ECM again. I'm so lost. This is ECM #5. I have to think there is an issue with the car somewhere, but I have been through all the fuses and everything is fine. The car communicated with the last ECM, just kept blinking the check engine light and wouldn't accept the emulation on my autoprom.

Here's the list of things I've learned today:

1. The vehicle is still in limp home mode with the autoprom installed
2. The vehicle remains in limp home mode with just the memcal installed and no auto prom
3. I no longer have a check engine light at KOEO
4. I no longer have a check engine light at all
5. The vehicle will not even communicate with my snap on scan tool
6. All my fuses are good.
7. I am beginning to dislike this car

As always, the tech support is appreciated.

DG

So on the phone with moates customer service today. Great guys, learned a lot today. They actually took control of my computer hooked up to car and went in and looked around a bit. Over the past year we accumulated additional Memcals and I just recently put a remanufactured ecm into it from advance auto. After a bunch of testing between different chips, and memcals, it appears as though the ECM is bad,... again... seems pretty unbelievable but I had the expert look at it and we both agreed. So back to the auto parts store to try yet another ecm. They must love me over there.

DG

Thanks again to everyone who helped me out with my MAT IAT sensor issue; this is the continuation thread to previous thread in regard now to ironing out the ECM issues

So here's where I stand. I know it seems like its taking me forever to get this car done but to my defense I only have a couple of hours a week to work on it. Last year I ordered a Chip from PCM's of NC. Great customer service BTW, they have been so helpful over the course of the past year. Believed that the chip was bad so I called them and they sent me a new one right away. I was wrong. We found the issue with the distributor and then the issue with the IAT sensor. I installed the new chip and the car barely runs. So I removed the chip and reinstalled the factory memcal and nothing else. Finally the car runs, and I actually drove it. But it doesn't drive well. As to be expected since the stock memcal is in and the car is lightly modified. So I called up PCM of NC again they sent me out a new tune on a BIN file, no questions asked. Unfortunately I have no way of putting it onto the chip so I ordered a Moates APU1 AutoCal figuring I like these cars well enough it was worth spending the money. After 4 hours of pulling my hair out I was able to burn a new chip. Installed the new chip only to find the car barley runs once more and the check engine light and fan is on. I decided to run the codes and see what I came up with. Plugged in the APU1, and it wouldn't sync, so I moved to the ALDU1 data logging cable and tried to launch TTS Datamaster. Again I was unsuccessful. Grabbing my last line of defense, my trusty old Snap on red brick I still was not able to check anything as there is "no communication with the vehicle." Take out the chip and everything hooks right up. Has anyone ever seen this before? I'm assuming there is an issue with the chip itself, but not a burning issue or a bad chip issue. Something else? Thoughts?

DG

Quote:

Yea, but whats interesting was that I did not receive the correct reading until I cut the wires. I can only assume something was back feeding through those wires causing the false readings and then failed tests.

The good news, even though I only get a couple of hours a week to work on it we are making really good progress. The car looks amazing now its just a matter of getting it to run amazing...

Which brings me to my next thread

Stay Tuned!

Ill just be honest, I don't know what I did to fix it but its fixed. Had to cut the wires exactly at the ECM and send out two new ones. Makes no sense. Only thing is that I've had to work a couple of bugs out of the this harness already. Its for a 91, I have a 90, and the guy before me made some "adjustments" as well which needed to be corrected. This car is quite the labor of love. Now I am exhibiting some tuning related issues but I have PCM's of NC helping me out with that. They have been great so far.

Thanks,

DG

Quote:

Yes! Lol, it is.

DG

Just found out diagram I have been working off of is wrong. I did locate the correct wires on the ecm. At the ecm im getting the correct reading and when I wire in the sensor I am finally getting a temperature, but I have no idea whats wrong with the harness. I might take the easy way out here and splice the wires directly from the ecm but I have to be honest I have a list of other issues here that need to be resolved including no horn and heater controls inoperable which likely means there are still bad grounds/wires hooked up incorrectly. This is proving to be quite the project. We have resided ourselves to the fact that this is just the way it is and it might take years to really resolve. I have been making progress, just very slowly.

Also, when I rev the engine SYS flashes on the speedometer read out. What the heck does that mean?

DG

Also, My tan wire is acting as a ground. When I apply my DVOM to 12 volts and the black wire lead to the tan wire I see 12 volts. When I do the same to the pink/black wire I get .07 volts. If I apply my red lead to the Pink/Black Wire and ground the black, my DVOM shows the pink/black wire giving off 12 volts... this is so strange.

DG

Hello everyone,

Still working on the 1990 Corvette we purchased years ago. I am slowing figuring out all the issues one by one. I recently replaced the distributor which took care of all the idle dodging. Now I have a low rpm misfire. My scan tool indicates that the MAT or IAT Sensor is reading -40*C all the time, no matter what I do. At the wires, one reads 0 volts (as I'm guessing it should, and the other reads whatever the battery voltage is. I replaced the ECM 3 times with no improvement. I checked the harness it looks good. I am totally lost. Found a flow chart on third gen, but it was no help... states I should replace the ECM lol! Need help,

Dan

Ok,

Sorry for the delay in response. Just been really busy. So I called the company and they offered to send me out a new chip with the same info on it. So I installed the new chip and now the car runs, and idles but its still running rough and the check engine light is on. So the chip was definitely bad but the problem still isn't completely solved. So I ran the codes on my OBD1 scan tool I just got tonight and it came up with a Code 41 and 42

Code 41, Cylinder select error

Due to the same ecm being used for different engines, it is important that the proper prom is installed for the particular engine, a incorrect prom, not installed properly, or faulty. Another cause is the pins of the harness are not properly connected to the appropriate pins on the ecm, and/or the grounds could be open. For V8 applications, ecm pin D3 is grounded.


Code 42: Electronic Spark Control Issue

Now,

I am running a Camaro distributor with an external coil on this car so I am not sure whether or not that could be the cause of code 42 but after a little research I am thinking the ECU is not recognizing the "chip" they sent me??? What's the deal. I can't see why I am having so many problems here...

DG

Been working on a 1990 Corvette for a few years now. You can check out the progress in my thread entitled "How not to flush engine oil." I ordered a tune from a company that has a fairly good reputation. The engine is lightly modified, ported heads, degreed cam, roller rockers, tpis miniram. I installed the chip at the same time I installed all these other parts and at first thought the injectors I chose were to big. So I replaced them with 22lb injectors and sent out for a retune. It still wouldn't run right. I came up with the idea to pull the chip out and put the factory one back in. Car started up, ran ok, and stayed running. I thought I had maybe got a bad set of injectors so I purchased another brand new set, installed them and reinstalled the tune. Cars not running at all. Took the tune out, car runs and idles. I need this car tuned because I am missing egr, air pump, cats, and have a lower temp thermostat. But I've never heard of a chip not working. I find it hard to believe a company that does this exclusively couldn't get it right 2 times. What are your thoughts?

Also I am located in the NY, NJ, PA Tri-state area. Who tunes these cars?

Dan

Hello Everyone,

Happy belated 4th this 2015. I haven't had an opportunity to post in a while over here so you all missed the Saga and drama. So to get you all up to date, a month ago we sent out for the mail order tune and the chip returned tuned for the 38lb ford injectors. Right from the get go we ran into problems. Car went from barely running to not running at all. Pulled the plugs and they were wet. Did some reading online and realized 38lbs is way to big. So we sent the chip out again and had it re tuned for 22lbs. The Ford Blue injectors were too big so we swapped over to a set of EBAY yellow 22lb injectors which are listed all over the place online. A while back I remember reading that there were issues with those injectors but my father not realizing purchased them anyway. We sent the tune out and had it re tuned a second time for 22lb injectors. Got it back, car was running but really poorly. I was beating myself up over the past couple of weeks; checking over all my work, wires, vacuum check, and so on. Couldn't figure it out. For kicks today I went back into the ECU to make sure the chip was properly seated. While I was in there I decided to pull the tune/chip and install the original chip for the vehicle. For the first time to date car started up and idled normally. Still runs a little off but in comparison its 95% to where it should be. I attribute that to the fact that the cam is degreed, there is no egr, and no air pump any longer, and we are running a stock tune with a tpis miniram. So, this is where we stand: Do not purchase cheap ebay yellow injectors they are not 22lb injectors as stated in the listing, they are 19lbs. I am going to purchase a new, quality set of 22lb injectors from a reputable source and install them with the mail order tune. One a side note I was able to drive the car for the first time today. Took it up and down my road, got it up to 50 mph. It seems like it has the potential to be a very nice car. I will post video at the conclusion.

Just wanted to post an update. Was hanging by my engine builder and inquiring about a set of cylinder heads I plan to have them mil for my personal LQ4 Chevelle swap project I will hopefully be getting started on next. Turns out a year or two later (?) they had a note book page with everything they did to this engine including measurements. So we made the executive decision to outsource the tuning to PCMs of NC (PCMS4LESS). I felt confident with all the information I had they could put together a fairly close chip. The car is not going to be a race car, just a quick cruiser really. So squeezing out every last pony really isn't top priority. I am highly inexperienced in tuning so this would have been something that would have probably taken all summer to get right and even then there is no guarantee I will be successful. This is a quick short cut to getting the project done fast and being able to use the car all summer.

So just for reference (so I can look back in a few years). The heads are fully ported and a 3 angle valve job was done. Light milling was done to get the heads flat which caused a very slight bump in compression. It has a set of 1.7RR and the stock cam was advanced 4 degrees. The intake is a TPIS Mini Ram and we will be switching back over to the FORD/BOSCH 38lb/hr injectors this weekend. The car has a set of full length headers into a set of high flow cats. The exhaust was custom fabbed by me and goes into an X-pipe with Dual borla mufflers.


This past week Dad installed all new moldings around the doors, windshield, windows, and the rear trunk glass.


The remainder of the checklist includes:

1. Swapping Injectors again
2. Mounting Coil properly
3. Completing A/C System
4. Install new chip
5. Timing


Trying to get this all done this weekend, so I can enter it in a vintage car cruise/rally next weekend. We will see how it works out.

Pics and Video's to follow,

DG

Would the APU1 do everything I need it to do? I would like to be able to program the car in realtime like an OBD2 vehicle if it came down to it. I had my 89 programmed years back. I remember cracking open the ECU and adding a chip, that was then removed, reprogrammed, and re-installed. Just want to make sure if I am going to spend $300 this will do everything I may ever need it to do.

DG

TUNING:

Looking like my original plan to have someone locally Dyno tune this is a fail. I don't know if it is any more or less complex than an OBD 2 car, but there doesn't seem to be any interest at all in doing it. It's looking like Matt's recommendation has been the best so far. Since we have done everything except the engine refresh and windshield in this car I am tossing over the idea of buying all the equipment required to tune it myself. Yes, I know; I don't need a lecture on how complicated tuning is, Ill be the first one to say I only loosely grasp the basic concepts, but how are you going to learn if you don't give it a shot. I understand how the different systems work together so the car runs. My Friend knows very little about fuel injection controls on a vehicle but is great with computer systems and programming. We spoke about a collaborative attempt to tune this vehicle together this past weekend. He's in if I purchase the equipment. So do two guys who know a little = one tuner? Maybe we will find out.

What equipment do I need to purchase from Moates to data log and tune? Which is the preferred program to use for a novice... or should I say novices?

DG

AIR CONDITIONING:

So today we decided to tackle the air conditioning. My original plan was to convert the system from R12 to 134a. I've converted systems before with mediocre results. I have been reading conflicting information online about how to convert the corvette system over. Some say drain the mineral oil and add PAG 100, others say use 150 and then there are sites that recommend PAG 46; then there are those who use ester oil because they believe PAG oil to be corrosive. I haven't honestly had the time to do the thorough research on this I would normally do, to get the job completed right. I have a good compressor and a new receiver dryer. The original orifice tube is in good shape. I have 3 cans of R12. What do you guys think. Convert it, or replace the o-rings and put back in the R-12??


One thing I am having trouble locating is an oil capacity chart for this car. My crappy FSM doesn't seem to have it. If anyone can post one that would be really helpful.

DG

Quote:

The windshield was outsourced. We had someone come by and install it. It was an older gentleman who claimed he had done quite a few in his time. He didn't seem to have any trouble getting the job done so I would assume it was fairly easy.

The numbers are the injectors are so small I can't see them. I need to grab a magnifying glass and I can get those for you.

10w-30 it is..

DG

One random question I just remembered which I will post now before I forget. Apparently my machinist installed a high pressure oil pump in this engine as it is running at 80psi cold and 70psi hot (no loss of oil pressure here). I am running Joe Gibbs BR30 at the moment, but I'm going to dump it out soon and put in some Mobil 1. They recommended a 10w-30 for it, but do you think it might make more sense to run a 5w-30?

DG

Quote:

That was a very helpful site. Just learned that the yellow Ebay Injectors we purchased are 19lbs instead of 22lbs which they are supposed to be which is probably why this thing is running super lean... in any event they will never work on this motor, so we definitely have to address this before we dyno the car.

DG

Some updates:

New Windshield



And a new roof that doesn't match and needs to be painted



And some new shoes... 17's and 18'S



Its coming along nicely. I ordered a Receiver Dryer tonight and a Variable Orifice Valve for a 1994 Corvette tonight. My plan is to install the compressor next week and retrofit the A/C for 134a.

Spoke to a local shop today that has a Dyno. They have a tuner they use. Their not sure he does PROM but if he doesn't we will rent the dyno and I will contact PCM's for less and attempt it that way.

DG

No kidding?? I've heard of tuning done where you can send back the data logging over the internet and they make the necessary changes and send you back the new info. Is this what you are referring to?

DG

I did a cam swap on my car. For years I was told by others how hard and scientific it was. Once I got down to the nuts and bolts it was actually pretty easy and a lot of fun. A couple of really good tips if I may: work slowly and make sure you torque everything back to spec. Clean the cam really well before installing it (I made this rookie mistake, thought the shipping oils were some sort of cam coating and installed the cam without cleaning it. it worked out OK for me, guess i got lucky), Make sure you have a huge breaker bar to break off the crank pulley bolt, and work slowly installing the cam so you don't nick the bearings.

Good luck

DG

I know its been a year since my last post in this thread but we I wanted to bring some closure to it. We had some free time this week to button it up a little bit and the car is 95% done. It runs, we found a dipstick for it that fits. The only thing left is to install the air conditioning and get it tuned. It seems to be running very lean, and on the stock tune it will idle but is barely drivable. I did take it up and down the driveway just to make sure the clutch engages and it seems good to go. This week my father scheduled someone to come and replace the broken windshield. Overall we are both very impressed by how it came out and were glad we saved another C4!

Now the next hurdle is finding someone to tune it. There doesn't seem to be many out there still working on PROM cars at least not from what I can find. Does anyone know anyone decent we can bring it to, to have it tuned properly. We are located in Orange County, NY so the best bet would be someone in the NY, NJ, PA tri-state area.

DG

New Corvette
CTS-V
Challenger Hellcat
C63 AMG

Pick one

Merry Christmas!

Found both thanks guys!!

Now its just a matter of buttoning this thing up.

DG

Vehicle Runs Very Well! Finally!

I will have some video as soon as I can find a dipstick that fits this thing. Its spraying oil everywhere. But today we got it running nice and smooth.

Turns out the pump came loose in the tank and connection on the fuel pump assembly sprung a leak. I took the pump out, fixed it and reinstalled it. 42 psi of fuel pressure later the car runs amazing. I guess after the first start, I had good fuel pressure and then it started to leak dropping pressure. So upon revving the engine it didn't have enough fuel or pressure to rev up. Now it revs nice and smooth. when I shut the motor I have about 35psi of pressure holding and about 42 at idle.

Now I have to work on getting the timing right. Its running at 1000 RPM's at about 18*. I haven't timed one of these in a while so I an sure I am not using the proper procedure.

Super excited that this thing is one huge step closer to the dyno!

DG

That's a beautiful truck for the price. Did the out the door price include your trade? Seems like an amazing deal either way. I would love to buy a new truck

DG

Happy Thankgiving Guys. Feel better Bill

Checked the firing order. Its fine... Then an hour later the fuel pump went bad again. I think its clogged. Pulled the hose and ran it off the battery directly to try and pump some fuel out of the tank and although its making noise, nothing is coming out. I don't know what the deal is with these pumps going bad but I am going to order a new one and try again.

DG

Quote:

Yup, brand new balancer. Why did that come to mind?

DG

I am going to check the firing order tomorrow and I will post back. The ticking could be new valves. When I rebuilt the heads on my LS2 they ticked a little until the motor broke in. Not too worried about that.

Quote:

Nope good question.

I didn't. I didn't want to run it that long until the back firing figured out. I just moved the distributor back and forth and attempted to find a spot it ran well. Figured once I achieved that I would get out the light.

6* right?

Dan

Got the 1990 Corvette that I have been working on running and idling but it doesn't really run all that well. If you haven't been following my threads, this is a car that had a fire in the engine compartment. The engine was trashed as well as all the wiring. Over the course of the past year we rewired the entire engine compartment, and installed a rebuilt motor with a TPIS mini ram. Today I installed a small cap Camaro distributor and an msd blaster 2 coil. Check out the video below. It hard starts and then idles, but pops like crazy when you rev it up. I will recheck my firing order as I think its possible I may have crossed a wire. I will also drain and refill the gas tank as I know the gas is really old. My question to the guru's is what eles might cause this? Is it possible that because I am running a stock tune on a lightly modded L98 with a miniram the car will need a tune in order to run properly, or should I be chasing something else down?

Quote:

Nope,

I sure hope you are wrong. I bought a conversion harness for $10... sure was hoping this would be plug and play.

Dg

Doesn't matter to me. I don't have any of the PCV hoses setup yet on the 1990 I am working on so I can route it so it goes back into the intake or I can use one with a vent. On my C6 I have one without a vent and so far I am happy with the performance. Just trying to figure out what the best direction to go in is. My C6 is supercharged and this is naturally aspirated.

DG

Yea, those are top of the line, but way out of the price range. I know this can be accomplished for less, however I don't want to settle for an eBay one because they are practically useless without baffling.

What are your recommendations on a oil catch can under $100 that actually works? I know each forum has their favorites.

DG

The coils I had on the shelf look beat, so I made a really simple situation complicated when I decided to research coils yesterday. Wasn't sure if I should go with an Accell or MSD. After reading about spark arc, voltage, and ohms, I decided to pickup the phone and call MDS. Purchased a Blaster 2 coil this afternoon

DG

I have a bunch of msd coils sitting on the shelf so I should be good to go. I am going to order the harness today, just want to take a look at the wiring again before I do.

DG

Purchased this one. Hopefully its decent and has the right gear.

DG

Its been running on the big HEI but after spending the last 4 hours reading about distributors, I think I am going to need to take a closer look at a couple of things. I am switching over to a 1990 Camaro distributor I will purchase from rock auto. Does anyone know if the factory cast distributor and whatever gear they put on those will work with the L98 Cam?

My other concern is distributor depth. I had 3 big cap hei distributors. The one currently in the vehicle was the only one that fit. The rest sat too high. I can't find any definitive articles online on how to properly adjust and set gear depth on this thing. Some say use shims, but how do I know the right depth? And what type of shim do I use. Supposedly you shouldn't stack them either because they compress. If anyone knows of a source with detailed instructions please let me know. For now I will order the distributor and wait for the parts to come in.

DG

As the title states, who produces a good quality, small cap distributor for our cars? Currently running an HEI on an L98 with a TPIS Miniram. The intake does not give my distributor enough room for movement. I need one that is plug and play and smaller.

DG

Great News!!! She runs. Not very well but I managed to get it to idle tonight. Purchased a fuel pressure gauge and put it on the engine. It produced 1 psi of fuel pressure. Pump was running so I checked all the lines and they seemed OK. figured it might be a weak pump so I ran over to advance auto and picked up a new stock one, installed it, and had 46 psi of fuel pressure instantly. Turned the key and it sounded like it wanted to kick over. It did take a few minutes but I finally got it to start. Had to keep playing with the distributor to get it to start and the gas pedal to get it to finally run. When everything is all said and done I manged to get enough advance to keep it running. It ran really rough but its not tuned and I don't think my distributor is advanced enough because it is contacting the TPIS intake and has very limited movement. So my plan is to replace the distributor with a smaller one that is more manageable, drain the fuel and replace with fresh fuel because I have a feeling the gas is bad as well, and have the car tuned.

One thing I noticed that is interesting. I am getting oil pressure, however it seems very high. I am running Joe Gibbs BR30, and I have 80lbs of oil pressure cold. This seems kind of high. Any concerns with this?

Dan

A decent quantity of fuel comes out however it doesn't spray out.

Its definitely getting fuel to the fuel rail now. I don't have a fuel pressure tester, but will buy one this week. My question is at this point, would low fuel pressure lead to a complete no start situation or just cause the car to run like crap?

DG

Something I noticed. Tach is connected however the needle moves down on turn of key, and does not indicate RPM.

This is interesting. Used a Noid tester to check for pulse at fuel injectors. Light is flashing indicating its ok. Fuel Pump turns on and I have fuel at the fuel rail. HEI spark tester shows spark. Checked TPIS minram system. It had ford Injectors. So we ordered new stock injectors. Installed them. Plugs are still dry... does not appear that the injectors are opening. Poured gas into the intake. It ran for 2 seconds and then shut off. I don't have any idea what I am missing here. I have power at the injectors, fuel, and spark....

DG

I think a brain storm of a list of things that are required in order for the injectors to fire would be a good place to start.

I was reading that oil pressure must be at 4psi at the sensor in order for the injectors to fire. I have to get a mechanical oil pressure gauge on this thing and check that as well.

DG