Non third gen question but any help would be apreciated...

The other day my s-10 started to run a little rough and the exaust smelled of gas. Threw a running rich code, too. My first thaught was to check the cpi injector. Sure enough it was sitting in a nice puddle of gas b/c it was leaking. Went out and bought another one to the tune of about 400 bux and popped it in real quick. No cigar!
Now it runs like total dog @#$%. I mean it just bearly idles and is totaly undrivable. Sounds kinda like its missing too. I can also still smell gas in the exaust.
The ignition is good, good spark quality, fuel pump sounds nice and strong, gave it a major tune up also. So im assuming that those arnt it. I had this problem a month or two ago but it went away on its own. No where near as bad though. I gave it a wet compression check to see if i blew a head gasket and it had good compression on all the cylinders. Could have blown one b/w then and now but seems unlikely now that I'm having the same symptoms again as before.

Thank *** for my camaro or id be SOL.

Anyone have any ideas? Maybe a sticking valve????

 

top...

 

few more hints about what its doing...
At idle it sounds like its missing real bad and it will almost die then come back to around 300 rpm or so. Bearly has any oil pressure at this rpm. When i give it gas, the motor will stumble and then start surging at all rpm ranges. This is all accompanied by a strong gasoline smell in the exaust and some smoke. The ignition system seems to be in good shape. Ill hafta look some more at it tommorow.
Anyone have any ideas???

 

What year? What engine?

Other items that would help:

1. Fuel pressure reading;

2. System voltage;

3. Any modifications.

 

I dont know why i didnt include this to begin w/ but its a vin w 1993 4.3 liter vortec, bone stock. The electrical system voltage is around 15 volts or so. As for the fuel pressure, i got around to driving it today and when the engine is under load, it runs fine, alot better since i got the new fuel injector unit in. Has plenty of power. Just doesnt want to idle. It idles reeaall rough and makes like its gonna stall and then it just manages to keep going. Also under light cruse the engine surges. But the fact that it runs fine under load suggests that the engine and fuel system are fine. I was thinking vacuume leak but ive never had one cause symptoms as BAD as this. Could it possibly be a bad EGR? The egr is an electronic unit so i cant think of any way to test it right now.

 

Yes, the digital EGR valves are a little different to diagnose. Think of it as the same stepper motor and control used on the IAC system but slaved to an EGR valve - since that's basically what it is.

I doubt that you have an EGR problem, since the ECM monitors the EGR pretty closely in digital systems.

You should have a CPI system on your 262. There are six individual injector nozzles in the system, with one central control valve/regulator unit supplying all these nozzles. One of the wires to solenoid coil may be grounded, or the valve may be mechanically stuck open, allowing constant fuel delivery to the cylinders.

Excessive fuel pressure may cause a rich condition, but pressure is already regulated at 55-61 PSIG in this system, so it is fairly high anyway. Pressure can be tested with a tap adapter at the fuel filter. Anything over 65 PSIG could be part of the problem.

The system relies heavily on correct CTS input and MAP readings, so it may be advisable to check these sensors before tearing the top off your intake plenum to look at the CPI injector and regulator. Aside from that, the CPI control scheme is just like any other TBI or speed-density EFI system. This changed a little in 1994, but that isn't affecting your vehicle.

Of course, all of this depends on having a reliable ignition system, since a dead spark will create unburned fuel in teh exhaust as well.

 

I drove it down to the dealer to have it diagnosed and they found that the EGR was stuck wide open because of heavy carbon build up. Doesnt surprise me, the cylinders have almost an 11:1 CR. The egr is what was causing the lousy idle and the smell of unburned fuel in the exaust. Funnny too because after i replaced the CPI unit, it didnt throw anymore codes and i couldnt get anything out of the ECM. Cost about another 150 to fix that dammit.

Thanks for your time and input Vader, i apreaciate it...

 

Loving it!!! After all that CRAP, after they go ahead and clean it, those idiots find out that the ECM is energizing the servo in the EGR valve at startup and idle and the only solution they can recommend is to "unplug it" for the time being. Soooo.... I have to pay those flunkies $240 just to pull the friggin harness out. I cant believe it!!! Hell, for that price i could buy a diagnostics tester and found that out myself. All i would have to pay my F'n index finger to pull the harness out is about half a calorie!!!! WTF??? Now i remember why i do all my own work!

 

I'm glad you found the problem. Too bad it got so expensive. For about $100 you could have purchased diagnostic software for your vehicle and hooked up with a PC or laptop. Even the ODB-II software I use was less than $300 with cables. Maybe it's worth a look for next time? You still have to purchase the parts, but there is something to be said for some independence.

 

To Vader.

I have been kicking around the idea of a laptop for a scanner and
was wandering what kind of software is good and how fast of a
laptop is needed.

Is there any benifit to a laptop setup over my Snap-On scanner?

 

i believe one of the members of this site has a free software package called WINALDL along w/ schematics to make a connector. Its supposed to give real time data output. I think his name is johanes. Cant remember. I have never used it before but do a search and maybe you'll find something.