Hi there

My name is Si...great site you have here

I have a Corvette...it's an 88 C4 Coupe L98

Basically the car has been sat in it's garage unused for 3.5 years. We did start it 18 months ago to check on her and she ran fine then she was put back away again.

I have recently been trying to put her back on the road.

To cut a long story short...

I have replaced:
plugs
dizzy cap
rotor
coil
HEI module
Fuel filter
air filter
Battery

the fuel filter was badly clogged and full of black liquid.

I now have good fuel pressure at the rail with ignition on.

I also syphoned the old fuel out of the tank and put in half a tank of fresh stuff.

I took off the throttle body and cleaned it and the IAC valve thouroughly.

All leads were checked and are sparking ok (and yes they are in the right order) the fuel pump is operating correctly and the maf sensor relays are working ok. There are no fault codes being thrown up on the ALDL connector.

The problem? it is very very difficult to start the car. A little squirt of EZ start into the plenum usually helps but even then it struggles...when it does fire it chugs slowly into life with my foot on the floor and runs as if it is missing badly...it sounds like a tractor not a vette.

I have to keep the throttle on or it dies and if i put my foot to the floor it barely gets above 3k...i think it hit 3.5k once but that is it...i ran it like this to temp and took my foot off and the revs drop and the car dies....

i am almost at the end of my tether with her....

at the moment i am thinking ECM or bad injectors?? dunno how i would check this....

ANy ideas would be much greatly appreciated...

from a desperate mancunian

Si

 

That black liquid in the filter, is also in the fuel lines and injectors. You need to take the injectors out have them cleaned. Next, disconnect the fuel filter, the return line and the feed line at the plenum. Blow compressed air through them to clean them out. Next take out the fuel pump and check the sock and make sure it is not clogged,

 

Hi Si I have posted a reply to your post on the CCCUK

 

SI
You have a classic case of multec (injector) failure. The car has been sitting and the injectors get clogged, the coils overheat and then you get your problem.

We recommend replacing with Bosch design III injectors that are e85 compliant. The additives that is in gas today is breaking down the seal between the injector orfice and the coil housing. This leakage shorts the coil. Cleaning multecs is not recommended due to the failure rate.
heres a link to look at:
http://fuelinjectorconnection.com/sh...&productId=134

 

cheers guys

this is very promising

new injectors would seem to be a good idea anyway...one question..how the hell do i get the old ones out?

 

si do you have any experience in auto repair?
if not, it is not something you would want to tackle alone.
any local auto repair guy with a good reputation would install them for a reasonable fee.

 

i am no qualified mechanic

however i have some experience of "tinkering" with old gm cars and also motorbikes....

it's cheaper if i can do it myself plus i'll learn something to boot

how much to ship a set of 8 to UK?

i dont suppose there is any way to avoid the dreaded duty

 

Si, replacing injectors is a snap. basic procedure:

1. remove pressure from fuel system
2. Disconnect fuel lines from the fuel rails with a quick release (very cheap, I think Halfords stock them)
3. Remove rails
4. make sure nothing falls into the intake
5. replace injectors by unclipping them from fuel rails.
6. Reverse procedure, make sure you use new o-rings plus some suitable grease (dielectric is usually fine)

Good luck from a fellow brit (living in the US. )

Andy.

 

hi andy

thanks for the advice....

forgive me asking silly questions....what exactly is a quick release??

i presume i can remove the fuel rails with the plenum intact or do i need to take it off??

if so...how does it come off...its confusing me a tad..lol

 

si sent you a pm

 

Si - apologies I forgot you have an L98, I was talking from LT-1 experience. A quick-release is a plastic piece of tube with a split along the edge; you wrap it around the tube(s) at the end of the fuel rail at the point the fuel line(s) connect, push it into the fuel line and it releases the line. very simple.

I am not sure about the fuel rail / intake configuration on a L98 - sorry, maybe someone else can comment!

Good Luck, Andy

 

oki doki

i got my fuel rail off !!

murderous job mainly because every nut and bolt on my car seems to be sezied and i end up rounding the bugger...grrrr

the difficult bit is gonna be remembering where everything goes and where i put all the bolts..lol

i do have one question.....why on earth would the vacuum pipe that connects to the egr valve NO)T be connected to it and somebody has blocked the end of it up????

i am baffled!

 

1988 L98's didn't come from the factory with Multecs. They had either Rochester Products #5235302 or Lucas #10108481.

The dreaded Multecs were introduced in 1989.

 

i definately had an injector problem

new injectors fitting and it lives!!!yay

but wait..no it doesnt...

i now have fault codes to investigate...hmmmm

23 and 36

 

23 Intake Air Temp (LOW)

and

36 Mass Air Flow Burn off circuit

now i actually removed both MAF relays (they are both identical) and checked them with a power probe and both seem to be working ok and have no burnt connectors.

so i am horrified to think it may be the MAF....

I cleaned out the plenum chamber so whether this effected the MAT sensor I dunno?? I used carb cleaner.

Or it could still be ECM ... I am getting so close but yet so far

on the plus side when i ran it out of the garage for the first time in 3 years the brakes werent binding....i just thought it wasnt gonna stop!! LOL

hopefully a fluid change will sort that!