Another low speed miss problem

[ßill]

This story started about a month ago, I had a fuel gauge failure, stuck on full. I didn’t drive the Vette every day or very far when I did so I lost track of the fuel and ran out of gas. Since then I’ve been fighting a low speed miss. The engine seems to run smooth when the secondaries are in operation. The first 2 spark plugs on the passenger bank (2 & 4) are running black, the rest are light gray. I suspect dirty primary fuel injectors on those cylinders. The computer is reporting code 65 (right side rich). More confusion, The ’90 ZR-1 has in the past been to DRM for the “450” mod. Does it still use stock injectors? Can the injectors be cleaned by a novice?

Thanks for your help

Bill

 

[jhong321]

I had the same problem with my 1990 ZR1 when i drive normal it would seem to bog like it was not getting gas. I took it to 3 places and got 3 different answers. I had the fuel pumps,injectors,coils, fuel filters all changed and still had the problem. I finally found this 1 guy who use to work for a chevy dealer and went to the lt5 training. He looked at the car for about a hour and found the problem. He said it was a spark plug that was arking to the side of the sparkplug wire. He showed me a sprak plug with a little line down the side of the plug. Since then it never did it again. I hope this will help you

 

[ßill]

Thanks jhong321 I'll look a little closer at the plugs befor I dive into the pennum job.

 

[Hib Halverson]

With the DTC65 and the black plugs, it's likely you've got fouled or leaking injectors on that side.

You can try a pour-in injector cleaner and the only ones that work are detergent-based. The two most common detergent-base cleaners are Red Line Complete Fuel System Cleaner and some varieties of the Chevron Techron brand.

If a pour-in cleaner doesn't do it, you may need to replace the leakers or try having the whole set cleaned off the car. There are many sources for off-car injector cleaning but one of the best is RC Engineering in California. Take a look at www.rceng.com

Also, if you're thinking about upgrading your injectors, RC sells the RC/Lucas injector which is a better choice than stock GM units.

 

[ßill]

Thanks Hib, thats not what I wanted to hear. It is what I expected to hear. I tried an injector cleaner, not one you recomended, it didn't work. I'll try either Redline or Chevron and see what happenes. If that dosen't work I guess I'll just have to suck it up and tear off the plennum. I've looked at the RC site and get lost. I don't know the specs for the fuel system (pressure & flow rate). Is there a part no. for the injector?
Thanks again

 

[jhong321]

if you buy the rc injectors tell them you are part of a few corvette forums and they will give you a discount. i just bought 16 injectors from them and the retail was 79 bucks each i was able to get them for $64 each. we run the 205 injectors.

 

[ßill]

UPDATE

I tried the Chevron fuel system cleaner, The engine ran better but still not right. changed plugs, no change. I ordered a set of the "205" injectors from R C Engineering. They should arrive today. I'll keep you posted.

 

[8388]

Running the fuel pumps with low fuel level in the tank is no bueno. Have you checked your fuel pressure ?

 

[ßill]

Running the fuel pumps with low fuel level in the tank is no bueno. Have you checked your fuel pressure ?

Yes I sure did and it is within specs. Thanks for the thought. I tried all the cheep stuff first, no dice! Still waiting for UPS

 

[ßill]

The injectors showed p Friday afternoon and I started the job. Family obligations (dinner) prevented finishing Friday eve, finally finished Saturday afternoon and what a difference. The beast idles very smooth at about 900 RPM. Those 11-inch rear tires being fed through 4.10 gears are really having a tough time sticking to the ground now. The plenum job was not as bad as I thought, I’m glad I didn’t have to go any deeper. R C Engineering (Carol) was a pleasure to work with and when several corvette forums were mentioned a sizeable discount ($64 vs $80 ea) was applied.

Thanks for all the help

 

[jhong321]

Hi Bill You mentioned earlier that your fuel gauge was stuck on full. I am having the same problem. did this happen when you filled your tank? And what did you do to fix this problem?


Thanks

Jerome

 

[ßill]

Yes I was stuck on full after a fill up. The cause was the float arm was hung up on one of those plastic hose clamps on the fuel line in the tank. Just realigned the hose clamp, problem solved.

 

[jhong321]

Thanks Bill I pulled the pump and did the same thing and it's working now

Thanks

 

[ßill]

Glad it worked for you Jerome. It sure is the cheapest fix I've done on the vette!

Bill