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?

I will have to listen later... 0300 and up not feeling well and I don't wanna wake the house up!

However, check for vacuum leaks... but I suspect the plug wires are off.

Check #5 and #7 plug wires first.
Real easy to have those 2 backwards.

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Yep, I did that once, 5 & 7

Can't see the video on my phone.

Dumb question, did you set the timing with a light?

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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

It is back firing because of the timing. You can't effectively set timing by ear, sorry. 6* btdc. Hopefully you put a new balancer on the motor when it was rebuilt.

There is a tick or something in there, too... donno what that is all about. Exhaust? Valve?

Confirm timing... that pop sound is really icky... check plug wires...

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.

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

DG

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Stock balancers have been known to slip after years of use. This will make it impossible to set the timing. Happened to mine.

IIRC, the balancer has a rubber core and metal center with metal outside... it's the rubber core that starts to spin... and it's much like a tire spinning on the rim.

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

Take off the filter, remove the after filter, too (I would hardline that thing and get rid of it entirely).

Then with the lines clear, using compressed air, blast those lines clear. Install a new line.

Order the pump from RockAuto... about half price compared to retail.

If you think the fuel is bad, then use a different type of pump to drain the tank , then fill it with fresh. If it's just aged, top if off with fresh gas and some fuel treatment to break up the excess moisture.

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

Congrats!!! That's AWESOME news!!!! Way to go! Great find, too! Worth adding to the "old car troubleshooting guide".

As for timing, there is a wire on the distributor, disconnect that, then set timing accordingly. the wire in question is tan and has one connector. The connector normally lays against the firewall between the distributor and the power brake booster. It can be a bitch... if only to find.

I have posted the base idle adjustment before if you search for it, that includes setting timing.

Found both thanks guys!!

Now its just a matter of buttoning this thing up.

DG

Glad to hear. Let's get some videos up!

Throwing this in here for good measure.