I have an 85 corvette that was running fine and went in for a cooling fan and valve cover gaskets. It came back with a missing and would not run good at all. Took it back and they replaced the air control fan(which I never heard of) so I think they meant Air control valve. It did not run right when I got it back and would not even get back to shop. This time it was the alternator was bad and had killed the battery and they said that was causing the bad idle and missing. Got it back and it ran like a champ. Drove it on Sunday and it ran great. Wednesday of that next week, went to take it for inspection and it was missing and rough idle and surging. Made it home and went to drive it later and check it out and barely made the block because it would surge but if you tried to give it gas, it was bog out. It died twice but would restart but surged and would die eventually because you could not give it gas or it would die. It is home now and will not crank. It turns over and will fire and try to start but will not start. I did however unplug the MAF and tried to start and it did same thing. I plugged the MAF back in and it ran great for about 2 days and now back to the same thing. I did clean the MAF with cleaner made for it but that did not help. Any suggestions. I am leaning towards something sticking. Right now from what I read, maybe the EGR valve. Can the EGR valve be cleaned cause I understand it is hard to get to in order to replace.

Something is keeping the car from starting.

A bad EGR won't do that. It would start, then sputter and die... Or start and run like crap.

Check the basics first, fuel, spark, air.

I am betting on either a dead fuel pump or a bad Ignition Control Module. I guess a coil is also possible, but check for spark and check for fuel.

Make sure the pump is priming. On a cold start, you should hear the pump run for 2 seconds to pressurize the system.

The ICM is located inside the distributor, below the rotor. It powers the coil, IIRC. When it dies, and they do, no spark.

Did it happen to have any codes?

Do you hear the fuel pump turn on for two seconds when you turn the key on initially?

I would check fuel pressure first. If you have good fuel pressure let us know and we'll go from there.

Thanks Guys for your help, this information is very helpful and I am going to do some troubleshooting as you both suggested this Saturday and I will let you know what I find. I suspect fuel pump as you both suggested. I forgot to mention in my post that the mechanic that did the cooling fan and valve covers also did plug, plug wire, distributor and rotor. This car had no running issues until after it came back from the shop the first time. That is when they did the Air Control Fan, which is suspect they meant air control valve. Then it was the alternator and it ran fine for about 4 days and then started the surging to the point you had to keep foot on the gas or it would surge and idle so low it would die. Then it got to the point while trying to see what was going on it would just barely idle and die, crank and idle real rough back to the house. You could not give it any gas or it would die. Now it will not even crank. If it does, it just sputters for a second and dies. You an not even pump the gas to keep it running. So I suspect fuel pump and will start there. Next I suspect the ICM, esp since the mechanic was under the distributor. Is it possible he messed up something doing is work under the distributor? I do appreciate all your help here. This car is giving me the blues. I have an 84 also and it fires right up and ready to go. The car I am working on it actually my Moms and she is very upset that she has spent several hundred on this car and it still will not run.

Hey Fellas,

I can hear the fuel pump when you turn on the key. It runs about 2 or 3 seconds and cuts off. When I got to the car today, it cranked and ran about 2 or 3 seconds and it dies. After that it will crank and die, crank and die. It seems to be starving for fuel in my opinion. I am thinking possibly fuel filter. I looked it up and it recommends and empty tank because otherwise you get a shower of fuel that never seems to end coming out of the fuel line and this car has about a full thank of gas. Any recommendations on changing this fuel filter at home because I can't get it to a shop without towing?

Realistically it is probably not your fuel filter, although that is a good maintenance item. You need to put an actual fuel pressure gauge on the Schrader valve on the fuel rail to see what the number is.

Ok, I will do that because I seriously think it is fuel starved. So I guess basically the fuel pump could be pressuring up but not maintaining adequate pressure to keep the car running?

Quote:

That is an absolute possibility.

You can rent a gauge for free at Autozone, you just give them a deposit. I've been using the Harbor Freight fuel pressure tester for about 8 years and it's surprisingly good. I had to replace an o-ring in the fitting, that's it.

You might have a weak pump (common), or it could be something greater like a wiring problem (which is less likely). It could be something as simple as a disconnected fuel dampener. Luckily, the fuel pump is about the easiest job to do on the C4.

Check the fuel pressure and get back, it should be around 36-39 psi.

Here is a write up on replacing the filter you asked about:

http://www.corvetteforum.guru/modules ... wtopic.php?topic_id=19259

Here is a write up on replacing the pump:

http://www.corvetteforum.guru/modules ... at&topic_id=12262&forum=1

OH man, this is great information. Thanks so much. I tested the fuel pressure and when I turn on the key the pressure only went to 2 or 3 lbs. I cranked it and it ran about 5 seconds and pressure never got over 10 lbs. As car was dying pressure was dropping. When it was running it was not running great and I assume that is because it was starving for fuel and as pressure dropped that is probably why it was dying. I am going to use your directions and replace pump maybe Monday or next weekend. I Thank You so much for all your help and I am confident we have found the problem. I will let you know soon as I get it replace and the outcome.

Definitely sounds like a fuel pump. Not to hard to replace on the C4. should take about and hour or two.

Sounds like you isolated the problem. Luckily it's a pretty easy fix. Get a new sock with it, as well.

I am also betting on the fuel pump. Considering the 3 lb reading, that's a real "duh" moment. Good find!

Check RockAuto for a replacement.

They have a lot of options, and the prices are EXCELLENT.

However, if it was my money, I would spend the extra coin and get the Denso pump. It's about $62. Yes, it is more expensive, but Denso has excellent quality and durability.

My 2nd choice would be the Carter, for $36.

Over in Corvette Chat, you will find a the Rock Auto 5% discount code.

As an aside, I got my last pump from Racetronix and it has been the BEST pump I have ever bought.

I would also replace the fuel filter. Get the WIX filter.
Excellent part. It is $8.70 at RockAuto.

Depending upon how brave you are, the fuel pressure regulator might need servicing. The diaphragm fails... causes loss of regulator function. Age is a good a reason as anything for a failure. Airtex has a diaphragm for about - eek! - $80.00!!

TPiS has the diaphragm for $42.00

http://www.tpis.com/parts/view/15

I would also consider a new mechanic...

This is all great information and I really Thank You guys so much. I plan to try and get this fuel pumped replaced this week and will keep you guys posted. I also have an 84 I am restoring and I am sure some questions will arise on it.

Let us know how it goes or if you have any trouble.

Yeah don't go cheap on a fuel pump. That's one of those single point of failure items. Or at least get good quality shoes because you'll need em.

My MAF failure had the same symptoms. But it sounds like yours is a fuel pump after all.... Or could even be a bad fuel pressure regulator, that's what keeps the pressure in the fuel rail va just blowing back into the tank.

Just wanted to update everyone. I have not had a chance to replace the fuel pump yet. It has rained every weekend and got rain forecast for this weekend. It might clear up enough on Sunday. Keep you posted and Thanks again for everyones help on this issue.

How did it go?

Well, weather finally cooperated and I was able to get the pump replaced and so far so good. That seems to have fixed it. Have not driven it yet and plan to be out in it this coming weekend but it cranked and ran fine in the driveway. I really do appreciate all of you guys help and I plan to stay in touch.

You are most welcome! And don't be a stranger!

Glad it's back up and running!

Glad that seems to have fixed it! Stick around, we're happy to help with anything else.

If you are looking for your post on the idle, I split it off into a new thread since it is a different topic.