SBC 350 TBI: Help w/ Error Troubleshooting

[nicholastheczar]

I've got my SBC TBI hooked up and running, but it has its problems. It starts off and runs when cold pretty solid, but when it starts to warm up it runs really rough, stalls, backfires, etc. I've got a ALDL cable and have been gathering data w/ WinALDL. I noticed my Throttle Position Sensor (TPS) was giving me a constant number and not changing. Tested it and it was bad. Picked up another one and installed it, works like a champ. That helped w/ my idle and when I give it throttle but like I said above, once it warms up, it runs rough, etc. I'm getting a error code 33 (MAP high (Manifold Air Pressure)) and a 45 (O2 rich (o2 sensor)). I'm wondering if I don't have some vacuum leaks somewhere. What do you guys think?

Here are some of my screen shots. Any help is appreciated.

Thanks,
Nick

 

[alex e]

Nick, just come by the shop, and run that on my TBI and I bet that will clear it all up............did you flash the ECU, by the way?

 

[nicholastheczar]

Also, here is a screenshot of my sensor data figures.

 

[nicholastheczar]

Nick, just come by the shop, and run that on my TBI and I bet that will clear it all up............did you flash the ECU, by the way?

I'll be more than happy to come up to the shop when I get it fixed

 

[alex e]

HAHAHA. Fine.BY the way, are you concerned about having the muffler right beneath you, versus tucking it laterally between the frame rails in the far back? Seems like you might smash it there beneath you. Very cool that is was $368......gives me hope.

 

[nicholastheczar]

HAHAHA. Fine.BY the way, are you concerned about having the muffler right beneath you, versus tucking it laterally between the frame rails in the far back? Seems like you might smash it there beneath you. Very cool that is was $368......gives me hope.

I guess I'll just have to see what happens, but I don't know how much actually hard core rock crawlin wheelin I'll do, but we'll see. I've got to get my error codes fixed first.

Nick

 

[nicholastheczar]

No one can give me an idea of what is causing my error codes? Bueller ... Bueller?

 

[cruiser enthuiser]

Hey Nick. I'm not much help here. I still get error 44 for lean exhaust which I understand can be a vacuum leak, exhaust leak, faulty o2 sensor, bad knock sensor, etc, etc, etc. I've tried many fixes but to no avail. So much of that data means nothing to me and I have not yet rolled up my sleeves and dove into any of the programming to get a better understanding.

Have you checked out thirdgen.org yet? Those dudes over there are amazingly knowledgeable on this stuff.

-Ed

 

[nicholastheczar]

Hey Nick. I'm not much help here. I still get error 44 for lean exhaust which I understand can be a vacuum leak, exhaust leak, faulty o2 sensor, bad knock sensor, etc, etc, etc. I've tried many fixes but to no avail. So much of that data means nothing to me and I have not yet rolled up my sleeves and dove into any of the programming to get a better understanding.

Have you checked out thirdgen.org yet? Those dudes over there are amazingly knowledgeable on this stuff.

-Ed

Hey Ed, good to hear from you. I checked out thirdgen but haven't posted anything over there yet, I probably will. I've been searching over there and there is a ton of info. I'll post up what I find. Thanks for the help. I know what you mean about all that data, loads of information coming in, but don't know what to do w/ it and what the ranges are.

Nick

 

[terrx]

The IAC counts seem high. At this stage it would be good to check "minimum air" if you haven't already. Web search should turn up lots of hits on the procedure to set it.

 

[nicholastheczar]

The IAC counts seem high. At this stage it would be good to check "minimum air" if you haven't already. Web search should turn up lots of hits on the procedure to set it.

Ok, I'll check this out. I pulled my air filter housing and watched my injector spray pattern and they are conical but have visable droplets in the spray. Sounds like a cleaning is in my future. I'm wondering if this isn't why my o2 sensor is reading rich; too much fuel going through / leaking from the inejectors. I read on thridgen that several folks there have used these guys for injector cleaning...
WitchHunter Performance - Injector Cleaning & Flow Testing Services

Might be worth it to try them out. Anyone here ever use them?

Nick

 

[terrx]

Haven't tried them, or had the injectors cleaned for that matter. The price seems ok. Knowing the true flow rate would be useful if you get into tuning. Before you send them off, be sure they are appropriate for the 350 and for the ECM. You want the orange & black 62lb/hr injectors, anything less aren't worth putting money into.

 

[Elbert]

check those little plastic vaccum lines around the top of the manifold, as i recal somewhat near TBI....very prone to cracking... I replaced all that crap with old school rubber hose and never had an issue again on the TBI pickup I had.

 

[nicholastheczar]

Haven't tried them, or had the injectors cleaned for that matter. The price seems ok. Knowing the true flow rate would be useful if you get into tuning. Before you send them off, be sure they are appropriate for the 350 and for the ECM. You want the orange & black 62lb/hr injectors, anything less aren't worth putting money into.

That is a good point. I just learned that this Throttle body is out of a 92 camero 5.0L and I have 5.7l in my 40. I'll check out the injectors. May have to buy new ones.

check those little plastic vaccum lines around the top of the manifold, as i recal somewhat near TBI....very prone to cracking... I replaced all that crap with old school rubber hose and never had an issue again on the TBI pickup I had.

I have all new lines and plugs on my intake manifold, throttle body, brake booster.

Nick

 

[Downey]

The VSS works with the Ignition Module to control idle functions, and it sounds like your problems are 1,000 percent idle problems. You should have a 2 pulse VSS, and hopefully the ignition system wired properly, and also definitely the correct MAP sensor for your particular ECU.

 

[nicholastheczar]

I don't have a VSS hooked up yet. I had bought one from Jags that run but had to send it back to get it to mate w/ my autometer speedo sender. I went to napa today and bought new injectors for my throttle body. Hopefully these new injectors will correct some of my problems (1) wrong injectors for wrong motor (2) dirty old injectors w/ bad spray pattern.

 

[terrx]

Did you verify the ECM is for a 350? Let us know the 4 letter broadcast code if you have it. It would be on a white label on the ECM. Reason I ask is that if it was also for the 5.0, it will be calibrated for the smaller injectors. Putting in larger injectors for a 350 will confuse it.

Napa sells a 10 (or 40?) micron fuel filter that would go between pump and throttle body, with 3/8 hose fittings. Between tank and pump you want something like 100-400 microns. I can look up part numbers if you need them.

 

[nicholastheczar]

My ECM came from a 88 chevy suburban and it is a 7747. When I get home I'll get the broadcast code. I'd like to get the fuel filter part numbers from you if you have them.

Nick

 

[Alz Toy]

Here's another site w/TBI swap info. Binder Planet, Bill Hamilton ( Bill usn-1 ), also hangs out on Pirate.

 

[nicholastheczar]

Thanks for the info. I put in new injectors and no difference. I'm going to borrow a vacuum gauge and test my vacuum and see what that does. I am also going to reevaluate my timing and retard or advance it and see what that gets me. I'm having trouble now w/ it loosing power at when it heats up and running VERY rough and won't idle worth a flip when it is warm. It starts caughing, sputtering, looses power.

Nick