Help! non-Vibe troubleshooting advice wanted

[silver_vibe]

I know this is a Vibe forum, but I've noticed some of our members work as GM technicians so I hope someone can help me...I have an 85 El Camino with a 4.3L V-6 that is stalling while driving. It appears to me the Throttle Body Injector (TBI) is injecting too much fuel and the car is flooding. I bought a whole new TBI but the same thing is happening so I think there must be some sort of electronic sensor that's malfunctioning and telling the TBI to inject too much fuel. I've read the TBI section of the Haynes Repair Manual but I either missed it or it doesn't mention such a sensor. Is there such a thing or do you think I need to replace the Electronic Control Module (ECM)?Any advice would be appreciated.

[ToolGuy]

Howdy! Have been away for a few... Still need help on this? Since you cannot answer now I will ask my GM Technician friends for you...

[ToolGuy]

Got a reply already!"On the 87, you can jump the A and B terminal, like the Corvette to obtain ECM codes.It could be an o2 sensor, coolant temperature sensor, MAP sensor or TPS that has gone bad.That is what I would suggest first."This is from a GM Master Tech friend of mine and he is good...

[ColonelPanic]

Todd, those were the days! I liked back when you could just jumper the port with a paperclip, wire, anything cheap and metallic that was readily available, turn on the ignition and watch the check engine / service engine soon light, whatever they called it that year flash. Scan tool, pfft! IIRC, GM stuff of that vintage flashes code 12 once (one flash, a brief pause, two flashes) and a longer pause before going to other codes. If it keeps repeating 12, there are no codes stored. I was going to suggest checking for codes, so you've got 'em on the right track.

[threekrows]

and when it does flash codes,it flashes them three times,then goes to the next code.code 12 is at the beginning and the end.If I remember correctly,code 12 is no tach signal to the ecm which makes sense as the engine should be off when checking for codes this way.Key on engine off....

[silver_vibe]

I just checked the OBD code and I got a code 33. Code 33 either means Mass Air Flow sensor or Manifold Absolute Pressure sensor voltage too high. I already checked the vacuum hoses from the MAP sensor. I will try replacing the MAP sensor, but I've read code 33 is thrown when the engine idle is unstable (which it is before it stalls).Thanks for the assistance, I now have several things to try.BTW - genvibers rule. I also posted the same question on an El Camino forum and got fewer responses than here. Thanks again. I'll post my results after this coming weekend.

[ColonelPanic]

There you go, you've got it threekrows. It's been a while since I've done that, I forgot about it flashing in threes! Hang in there silver_vibe, you'll get it. I remember my good ol' 82 Monte with the 229 that horrible computer controlled Dualjet carb it had, it was a challenge to keep it running smoothly. IIRC, I think it threw a number of 33's in its day too, so what you just said makes sense. *sobbing* I wish I had that car back... but anyway...With yours flooding out like that, I wonder why you aren't getting a code where it was running rich? Maybe, just maybe, there's that one vacuum line that's disconnected somewhere that's buried, good grief were there ever a ton of those!

[silver_vibe]

Quote, originally posted by ColonelPanic »...Maybe, just maybe, there's that one vacuum line that's disconnected somewhere that's buried, good grief were there ever a ton of those! That's exactly what I thought before I posted here. I spent a good hour and a half last saturday checking all the lines. I even thought I hit paydirt when I found a worn vacuum line (worn right at the clamp so it was hard to see). I replaced the line, but it's still idling rough and stalling once it warms up.Looks like this coming Saturday is shot. Well, if I can fix it, it's a good Saturday...if I can't, it's shot.

[ToolGuy]

CP, you got that right! Simple times back then... Forget all this OBDII crap and sensitive sensors for if you even burp in your car possibly setting off the CEL! I had a 1987 Cavalier RS and my brother had a 1983 Regal with OBD and a carb still. In fact I just pitched a hand held code reader or glorified paper clip for OBD but it did have the code definition book. Threekrows has the info/memory still it sounds like.

[silver_vibe]

OK, it was not the best use of my Saturday After checking the reference voltage to the MAP sensor and the voltage when connected, i concluded that was the problem. I replaced the MAP sensor and then the car wouldn't start at all. I cleared the OBD memory and then tried to start is again...this time I got code 22 (throttle position sensor). Since that is part of the TBI, I reinstalled the new one I have. The car still won't start and now I'm getting code 33 again! $%*#!@I may invest a little more time in this, but I think it may be time to bite the bullet and tow the car to a mechanic.

[silver_vibe]

I got it! I double checked all my connections and the new MAP sensor connector wasn't all the way in So bottom line, I had two issues with my car: 1) bad MAP sensor, 2) bad throttle position sensor (GM Master mechanic nailed it - thanks!)Not only is it now running, it's finally idling at the correct RPMs. Since I bought the car in 1999, it's been idling too high. All I have left to do now is adjust the timing.I have one more question (I know it's a long shot in this Vibe forum): while checking all my vacuum lines, I noticed my EGR control solenoid floating behind the TBI...where is it supposed to be attached? It has two vacuum lines on top and (what looks like) one at the bottom in the center of a clip...but the one at the bottom isn't connected to anything.

[ToolGuy]

Quote, originally posted by silver_vibe »I got it! I double checked all my connections and the new MAP sensor connector wasn't all the way in So bottom line, I had two issues with my car: 1) bad MAP sensor, 2) bad throttle position sensor (GM Master mechanic nailed it - thanks!)Not only is it now running, it's finally idling at the correct RPMs. Since I bought the car in 1999, it's been idling too high. All I have left to do now is adjust the timing.I have one more question (I know it's a long shot in this Vibe forum): while checking all my vacuum lines, I noticed my EGR control solenoid floating behind the TBI...where is it supposed to be attached? It has two vacuum lines on top and (what looks like) one at the bottom in the center of a clip...but the one at the bottom isn't connected to anything.EXCELLENT!!!! I will tell my friend, his name is Paul... He has helped me a few times with my cars and knows his stuff. I in turn have helped him with tools. It is like having a tech in my back pocket! For the EGR, no pic in the serv manual for reference?

[ToolGuy]

I never would have thought but under my access to the GM service manuals there is no serv manual procedures going back that far but there are TSB's, bulletins and other docs still! Very funny! I did find this one... LOL!!!SERVICE MANUAL UPDATE UNSTABLE OR INCORRECT IDLE #88-269-6E - (Jun 6, 1988)Model and Year: 1981-88 CHEVROLET PASSENGER CARS AND LIGHT DUTY TRUCKSWhen using the 6E Section "B", Symptoms For a Rough, Unstable, or Incorrect Idle, make sure to check the motor mounts for damage, grounding out on the frame, or mispositioned, etc. Add this check to all Section "B" symptom tables under the heading "Rough, Unstable, or Incorrect Idle."General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.

[silver_vibe]

Quote, originally posted by MiVibe-ToolGuy »For the EGR, no pic in the serv manual for reference? Not in the Haynes manual I've been using...I need to invest in a better book...does Paul have any suggestions on a good service manual for an 85 4.3L TBI engine? The Haynes manual I have tries to cover too many engines types over too many years and lacks details (IMHO).Update: now I'm getting a CEL when the car is cold. I checked the OBD and I get a code 32 (EGR closed at engine start-up). If I turn the car off and then back on, the light CEL goes away and does not return for that entire trip. I guess I need to figure out where that EGR control solenoid is supposed to be connected. My engine is also stumbling when I try to accelerate hard (oxygen sensor?).

[ToolGuy]

Sorry I have been away for a few days...For service manuals try this guy: Email Bob at parts@fichtnerchevrolet.comHe is at a GM dealer and gets friends of mine their Corvette manuals. I am sure he could get new or you never know a used set for you. I have never used Bob but he is always recommended for service manuals and parts on the one Vette site I belong too. It is worth an email...Or search eBay for manuals... As for the hesitation... How new are your plugs and wires? Is the converter original or has it been replaced? Have you ever run fuel injector or in your case TB cleaner through the engine?

[silver_vibe]

Quote, originally posted by MiVibe-ToolGuy »How new are your plugs and wires? Both (plugs/wires) were replaced approx 15-20,000 miles ago. I pulled one plug and checked it and it looked good. Quote, originally posted by MiVibe-ToolGuy »Is the converter original or has it been replaced? Cat is original with approx 180,000 miles on it.Quote, originally posted by MiVibe-ToolGuy »Have you ever run fuel injector or in your case TB cleaner through the engine?No, but I just installed a new TBI (see above) and the engine was rebuilt about 15-20000 miles ago.I've been driving the El Camino to work all week. Aside from the hesitation, it's running great. My gut is telling me the hesitation is one of three things: EGR valve, EGR control solenoid or vacuum leak. I will search for a shop manual on ebay. Thanks!(EDIT: I just checked ebay and found the 1984 and 1986 shop manuals, but not the 1985. I know the 1984 won't work for me. The 1986 might, but bidding is already up to $57.00 and there are over two days left in the auction.)

[ToolGuy]

180,000 miles! (removed)! That is a lot for a cat! That pretty much is gong rate for used Service Manuals. I have sold them before and usually get anywhere from $50-$100 depending on the vehicle. For the EGR and see how the engine is after that is fixed. Like you said it just very well may be that and only that.

[silver_vibe]

Quote, originally posted by MiVibe-ToolGuy »That pretty mush is gong rate for used Service Manuals. I have sold them before and usually get anywhere from $50-$100 depending on the vehicle. I bid $6.99 for one on eBay last week and I was the only bidder! So I got one for $6.99 + $5 shipping. I won't believe it until I have it in my hands, but for now I feel like I got an incredible deal on eBay.

[ToolGuy]

Quote, originally posted by silver_vibe »I bid $6.99 for one on eBay last week and I was the only bidder! So I got one for $6.99 + $5 shipping. I won't believe it until I have it in my hands, but for now I feel like I got an incredible deal on eBay.Wow that sounds like a great deal!