What happened?

[DAVZKAR]

Car running fine ,stopped for gas and twenty minutes later rough idle , no service lights or any codes. No power either . I put in a bottle of gas dryer hope it helps. I stopped at a locale Shell station. If it is the gas I am going to make them pay for their carelessness. What else could do this and throw no lights or codes? ad ad ad ad ad

 

[90 Corvette ZR-1]

just a rough idle, no missing or hesitating?

 

[DAVZKAR]

Yes it misses, jerks, all that. I think it has got to the injectors.

 

[90 Corvette ZR-1]

Yes it misses, jerks, all that. I think it has got to the injectors.

at all speeds or just idle? if it is all speeds pull the plenum and test the injectors

 

[tomtom72]

Hi Dave, Just another novice Z driver here. Mine is doing the same thing. No codes & big time miss with & without the secondaries. You could pull the plugs & eye'em for cracks or fouling. I don't know if testing the fuel pressure will show anything, I'm doing that next. Do you have a Helm manual? If you do in 6E sec are the driveability issues, at least in the 90 manual that's where they are.

I'm eyeing the ECM plug diagrams to see if I can test the primary injectors for Ohms w/o pulling the plenum. If it works I'll post here. I found if less than 12 ohms = bad injector by looking at other forums, can't seem to locate that info in the Helm manual. I'm probably not looking in the right sections.:confused

I filled up & it started missing but I think it's just a concidence in my case. Tried the chevron Techron stuff & no help.

Tom

 

[JRMaroon]

It could even be as simple as a loose gas cap. Sounds too easy but I've seen this cause a rough idle and miss condition.

 

[JJS]

I hope you got a receipt when you paid at the station, if in fact it turns out to be a problem with the fuel.

 

[tomtom72]

Okay, Gas cap noted

I apologize to Dave! I'm not trying to Hi-Jack the thread. I was gonna start one myself but I felt we seem to be in the same fix so I jumped in here not to waste server space? If I'm out of line, I apologize to all.

The gas cap? I never in a million yrs would have gone there! I'll try it. Why, is it because of the evap. sys.? Anyway thanks for the easy suggestion, JRMaroon!!
Tom

 

[vette-dude]

I apologize to Dave! I'm not trying to Hi-Jack the thread. I was gonna start one myself but I felt we seem to be in the same fix so I jumped in here not to waste server space? If I'm out of line, I apologize to all.

The gas cap? I never in a million yrs would have gone there! I'll try it. Why, is it because of the evap. sys.? Anyway thanks for the easy suggestion, JRMaroon!!
Tom

Dave has another thread on the same subject in onther forum. If you have the same problem then it ain't a Hijack!! Hope you get it fixed.

http://corvetteactioncenter.com/forums/showthread.php?t=73235



Randy

 

[tomtom72]

Hi Randy, thanks for understanding! Interesting that thread & the part about the coils. I think I'll look over that also.

I feel bad for what happened to Dave at the dealer. J***s K ***t those guys have the testers to check the injectors & the ignition system!!! WTF! I'm a back yard smuck and if I had their equipment I think I could figure out a bad coil.

Tom

 

[DAVZKAR]

Tom did you find out what was wrong with your car? Mine turned out to be a bad coil. So while I was there I replaced all the coils and new wires too. Now the car runs great. The Idle has even dropped back to where it is suppose to be. The coil just went when it did. I was disappointed not to be able to drive it to Carlise. But I learned alot about the car in the process of fixing it.

Dave

 

[tomtom72]

Hi Dave, Thanks for the interest. No I'm still chase'in things. I checked the fuel & spark. Can't get it to set a code. I checked the ohms on the primary injectors. Checked all the grounds the ECM plugs use. A local tech told me it is probably the ECM. So I hit up AZone for a reman'ed one. I'll know when it gets here. In the mean time I'm collecting all the parts for a plenum pull: vacuum system, ignition system and RC injectors, etc. Whatever is under there I'm changing out.

Glad to see yours is up & runnin

Tom

 

[DAVZKAR]

I hope you get it straight soon. The CAC is a good group of people. I just started to post on the ZR1 NET/ REGISTRY too .There is a lot of experience there too. You can also talk to Marc Haibeck. You can access him from there. Well best of luck to you.
Dave

 

[tomtom72]

Hi Dave,Yes the people here and at the Znet are the main reason I went for a Z! Just knowing some one's got your back is excellent.

Thanks for your support. I'll get'er done...eventually:L


Tom

 

[Tommy L]

Check the rubber line that goes to the map sensor on the rear of your plenum... may have come off or have a crack in it.

 

[tomtom72]

Thanks Tom! I changed hoses/checked the hose & the MAP, no joy. I checked gas for water w/ a dye, changed Fuel Filter, checked for spark and checked the ohms on the injectors thru the ECM harness, looked for codes, and came up empty.
I'm still investigating but I know I'm out of my depth on this electronic stuff.

Thanks for the shout!
Tom

 

[Tommy L]

Does your speedo work? if not check your speed sensor, my car did the same thing and it would stall every so often...just a guess, but worth a try.

 

[tomtom72]

Hi Tom, Yea my speedo is okay, but I'll check the electrical connector on the VSS anyway. If the VSS goes down the speedo stops working? Yea, I guess it would, jeeze I'm not too sharp. It's an electronic display and no speedo cables, right. I gotta stop thinking early 70's C3's!:L

I'll check the connector just to be sure but I know my speedo was working the last time I drove it.
Thanks man!
Tom