Mustang_Eater

Hello All,

Just picked up a 1989 Corvette. Didn't think it was a problem until I saw a youtube video of a guy starting up his Vet and it started almost immediatly.

With my Vet I have to hold the key down for about almost 4 seconds with the car turning over before the car starts? Any ideas why?

Note: If I hold it down and then let go and then try again it start immediatly..... Is this the fuel pump? If so anyone have any info on replacing them?

dogfish246

Here is my expierence: My Vette stopped starting on the first crank and would have to turn over a few times before she started. I did some tests and it ended up being the fuel pump that went bad (leaking check valve)...

The first test I would do is a fuel pressure test. I got my fuel pressure gauge for $20 shipped (I can give you the link) just in case you dont have a fuel pressure gauge.

I put the gauge on with the car off. Then I turned to the key (dont start) to prime the fuel pump. The pressure should go up (I dont know what your pressure should be for the L98) and it should stay up for over an hour.

If it bleeds down then now you need to go and remove the fuel filler door and clamp off the fuel line, that goes to the fuel rail, right after the pump is primed (this is a 2 person job)...

Now if the pressure stays up, you know its something with the fuel pump. If it bleeds off, it could be injectors, the fuel pressure regulator, etc...

If you have any questions feel free to ask, I know the process so it I might not have been so clear to you...


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If its the fuel pump here are some instructions for the fuel pump replacement...

Its pretty straight forward. The hardest part was getting the hoses off the part the runs into the tank.

Steps (from memory)

1.) Disconnect battery (make sure you dont take chances around gasoline)
2.) Take off the rear gas filler door with 4 star-head shaped screws
3.) Take out the rubber around the filler tube and now the gas tank and the fuel filter assembly top will be visible (be careful to not rip the rubber boot)
4.) Take off all of the hoses that connect to the top of the assembly (maybe hit the hoses with some wd40 the night before)
5.) Unscrew the bolts that hold the assembly to the tank and be careful because there is a gasket that would break up and fall into the tank
6.) There should also be an electrical connector that you need to disconnect too
7.) pull out the whole fuel pump assembly and get it on a workbench
8.) change out the fuel pump and fuel sock (the original sock was really tough to get off so I just ripped it up and tore it off)
9.) Thats pretty much it, take a pic of the fuel pump assembly so if you are a little confused putting the new pump in you have something to reference!

I think that is all, good luck!

94z07fx3

It could also be the fuel pump relay. Easy test is to turn the key from off to run (not start) and listen for the fuel pump to run 2 seconds then shut off. With a blown fuel pump relay the fuel pump won't power up until the oil pressure fuel pump switch sees about 5 PSI of oil pressure.

Mustang_Eater

Where is the fuel pump relay located? Thanks I will give it a shot! Also, Thanks Dogfish I will consider what you said!

94z07fx3

I'm not sure where it is on an L98 car. It may be just inboard of the powerbooster on the firewall. Some L98 guy will confirm I'm sure. But listen for the pump with the key on. If you hear it run then it's not the relay.

Mustang_Eater

Ok, I can hear the pump run for about 2 seconds then stop but the car still takes about 4 seconds with me holding the key down even after that.

I just called a auto parts store and I can get a new fuel pump for $52.00 and the complete assemble for $370.00 but would just the pump have the check valve on it that could be why it's not working? I really don't want to pay $370.00 for parts that don't need replacing.

Any ideas would be great!!! Thanks!

NOTE: Once the car start it runs just fine! Don't know if that helps any with figuring out whats wrong....

dogfish246

All you need to do is replace the pump... Not the whole assembly... The best thing to do is a fuel pressure test...

1stvet87

A good GM service technician i know called this a long crank issue. I had the same problem with my chevy pickup. I replaced the fuel filter and the truck would start in 1-2 revolutions. My vet will do the long crank thing when i put low octane gas in it. With the premium (91-93 oct) it will start quicker and seem crisper.

jnealg

fuel pump and filter is my guess. maybe injectors but my money is on the pump.

you will have to get a fuel pressure gauge. you wont regret it. $50 at most autoparts stores.

mine had a bad check valve that manifested itself with a lean bank code. I put a meter on the fuel rail and found the pressure ok when the pump was on but it would fall to zero when the pump was off (bad check valve). yes the check valve is part of the pump. you dont need the entire assy.

I had already replaced the injectors for other reasons so they were not part of the code I was throwing.

you need the gauge, get it. OBTW the repair for the pump was only a half beers worth of work. a whole one if you'r a drunk.

Filter otoh is a small nightmare. at least of my LT1

mine starts with a flick of the key.

hooked073

you did not say if the car was hot how long it has to sit if it is all the time ect. Need more information just to try an educated guess...

Mustang_Eater

NOTE: The car was hot doing my testing and I still had the hard start during the testing.

Ok, I got a fuel pressure gauge and it stays at 40 atfter I put the car to run. After the car starts it actually goes up a little but never goes down. I had the car running and disconnected the Fuel Pressure Regualtor and the pressure went up 10 psi just as I read it should.

The only thing I can think is wrong now is the spark plugs?

Lastly, I found this part melted to another part of the car today. It was melted to that thing with the white cloth on it..... Attached are pictures of it. Any idea what part it is? And could this being a little melted be the reason for the hard start?

Thanks!

dogfish246

Interesting, so I guess your fuel pump is good...hmmm

Damien89

This is an issue that many 89's have including my dad's 89.

Never really bothered us, so we let it that way as it starts each time after 4 sec or so.

If you want to try and repair it you will start throwing money for parts that you really don't know were the issue is. My advice is leave it as it is if it starts every time.

Aurora40

FYI, the white cloth thing is the heat shield on the EGR tube. I don't know what that sensor is sticking out, maybe it is the EGR valve, but it doesn't look like it would be able to close off flow through that pipe? You can buy new heat shielding if you are so inclined.

That connector to it looks bizarre, but maybe that is how it was from the factory?

jnealg

Fuel pump is good. ?Thats a good start on diagnosing rather than throwing parts at it. You will use a tool a lot longer than a part. :thumbsup

It looks like you have stock injectors. check those too before ruling out the fuel side. lots of posts on here on how but it boils down to measuring the resistance on the plug. Its not conclusive but you can spot a bad one if you see it. IF you need or want a set of used stock ones to tshoot with let me know. I just replaced mine simply because of the mileage.

Then its on to electrical I guess. I dont know what that plug is (my FSM is at home) but if I remember to look it up this evening I'll let you know. Maybe someone knows off the top of there head?

1stvet87

Just went and looked at my 87, it has the same sensor and connector except mine is routed back between the distributor and the firewall and does not cross over EGR tube. It looks like it would have to function similar to an O2 sensor, measuring exhaust gas.

1stvet87

Found it. I believe it is the EGR temp sensor. Check Autozone web sight. I don't know if a false reading to the ECM for EGR temp would cause a long start issue. Might try to repair burnt wire, then reset ECM by disconnecting negative battery terminal and see if that helps.

engle1147

That is the EGR temp sensor - that is the factory connector- nothing to go bad there unless the wire is broken or grounding on something nearby.

The EGR is not your problem.


Looks like you've got some new-ish Bosch type 2 injectors in the fuel rails. The cold start crank times on my '89 increased slightly at the same time I installed my first set of Bosch (type 2) fuel injectors with a slightly different coil resistance reading.....this may be a coincidence....but you asked for "any ideas."

jnealg

hmm I cant see the clips but they look like the fat stock multitechs to me. My eyes are terrible though.

1stvet87

Not saying the EGR was the problem. I am saying since the EGR temp sensor wire was melted to the tube it could be grounded out causing the ECM to change fuel or timing settings to compensate for what it thinks the EGR temp sensor is telling it. Whether or not that is causing the delayed start, it needs to be repaired and eliminated as a contributor to the problem. Just my 2 cents worth.