need help with injectors

[Freestyle21]

I recently purchased an '88 coupe. The previous owner said it needed new injectors - he had it checked by the dealership - I have driven it a little, and it runs a little rich. Lately it has had trouble idling until it's warm, it sputters and dies, the last time I drove it it stalled out at low speeds and corners.

2 Questions:
1. Does it sound like only injectors? I think it may be more.
2. What size injectors are stock? I can't find any information anywhere. The math says I should use a 19lb but the shop says it's a 22lb. I'm lost, anyone know?

Thanks,
Richard

 

[Ken]

If you think your injectors may be in need of service, one of our affiliates here at the Corvette Action Center is Witchhunter Performance. You might want to check with them to see what's involved in having yours cleaned.

 

[vette1985]

Hey Freestyle, If you find you need injectors, I saw SLP had some 25LBS ones for 99.99 for set of 8 on their website. Does not hurt to call them and check them out. For that price, buy them anyway.

 

[tntcorvette]

I recently purchased an '88 coupe. The previous owner said it needed new injectors - he had it checked by the dealership - I have driven it a little, and it runs a little rich. Lately it has had trouble idling until it's warm, it sputters and dies, the last time I drove it it stalled out at low speeds and corners.

2 Questions:
1. Does it sound like only injectors? I think it may be more.
2. What size injectors are stock? I can't find any information anywhere. The math says I should use a 19lb but the shop says it's a 22lb. I'm lost, anyone know?

Thanks,
Richard

Does your service engine soon light come on? If so you can check for trouble codes by jumping two connectors on the alcl which is under the dash right by your right knee. Just jump the two upper right ones together and turn on the ignition switch. THe cooling fan should come on and the service engine soon light should begin to blink...once then twice fast. It will do that 3x and if there are any codes it will blink the codes after that.

If your car is stock, then i'de stick with stock lb injectors.

 

[vader86]

I would at least have the stockers sent out for servicing, Rich at CruzinPerformance is good.

Stock is 22lbs, though you can run Ford #24s and they are cheap, but it would be advisable to install a pressure regulator to turn down the FP and help the ECM compensate better.

If it sputters and dies like that, it can be injectors, but I would check out the ignition system thoroughly and the MAF and O2 sensors especially. They should both trigger codes but they do not always do so.

 

[switch]

Check out the easy things first before yanking the injectors. Ignition, fuel pressure, vacuum, and exhaust leaks are a good place to start. You may want to see if the fuel pressure holds after shutdown, that will show a gross fuel system problem.
My shop does a comprehensive injector test for $5 each, or a complete test & cleaning for $12 each.
I don't recommend going to a different size/type of injector unless you are prepared to do some tuning. Some folks say you won't need to, but more often than not...you will.

Best of luck with your new vette

Gordon
WitchHunter Performance
Fuel Injector Cleaning & Flow Testing

 

[WhalePirot]

Perhaps the injectors need cleaning. Some time ago, on this forum, there was information from a GM engineer citing a study of cleaning options. He said that two or tree tankfuls of detergent gasoline cleaned filthy Firebird injectors, without pricey additives or shop visits. You have to drive anyway, so use a detergent gasoline.

From what I have heard, I am not a fan of oversizing injectors and turning down the fuel pressure. This is discussed elsewhere on the forum.

The cold running issue seems to point to the open loop phase, before all the sensors are involved in running the car. As such, I'd follow your instincts and check the things basic to any gasoline engine since before ECMs, like vacuum leaks, tune-up items and the like. The ECM can cover up and make us forget that, under it all is still an engine with all the possible foibles of those of the 'old days'.

 

[switch]

Perhaps the injectors need cleaning. Some time ago, on this forum, there was information from a GM engineer citing a study of cleaning options. He said that two or tree tankfuls of detergent gasoline cleaned filthy Firebird injectors, without pricey additives or shop visits. You have to drive anyway, so use a detergent gasoline.

Chevron's Techron gasoline will keep injectors pretty clean if used regularly, especially the newer style ball and seat types. Unfortunately the stock injectors that came in your car are an older design that are more prone to getting clogged. I have had to, at times clean them repeatedly(as many as 10 cleaning cycles) to get them to flow within a few percent of each other.
Besides getting dirty, there are a few things that can go wrong with injectors:
Internal or external leak.
Weak or broken spring.
Broken pintle.
Coil opens, shorts, and partial shorts.
And corrosion from water in the fuel system.

Hope whatever problem your car has, you can find and repair it without too much expense. Good luck.

Gordon
WitchHunter Performance