Chevy Tbi problems

[stx4wheeler]

I'm having problems with my efi setup. The motor is completely stock and I did nothing to it during my build. The only thing I changed was the fuel tank and pump.

The problem im having is it is running extremely rich. With the fuel pump plugged in and running you can only get it to start maybe once out of 6-7 times and to get it to start you have to hold your foot the the floor and keep it at wide open throttle once it's running as soon as you let of the gas it kills it.

If you unplug the fuel pump it will run like normal until it runs out of gas. I also tried reconnecting the fuel pump once it was running and it immediately floods it and it dies.

We tried unplugging one injector and it still wouldn't work. We also pinched down the hose that runs from the tank to the hard line on the supply and this helped a little in the fact that it would start, but then die right away. I then checked the return line thinking maybe it was plugged and was creating to much pressure in the system. My only other thought it the fuel pressure regulator is screwing up or could it be a bad sensor?

Flem, or Fred do you all have a clue? If you think you have an idea please post up!

[AggieTJ2007]

sounds like the fuel pressure is too high, what are you using for a regulator.

Can you measure the fuel pressure?

[Sharpe]

What pump did you use?

[stx4wheeler]

The regulator is the stock one on the throttle body, the pump is a stock replacement that came from krebs blazer.

[Fredo]

Sorry for not calling you back. I've been ay Goodguy's for work all weekend.

It sounds like you have a good sized vaccuum leak. Make sure you have all the unused ports plugged. Also, pull vaccuum on your brake booster and see if the diaphragm isn't leaking. If it isn't a vaccuum leak, it could be a bad pressure regulator or the injectors are stuck open and just pissing in the intake. Check the spray pattern of the injectors by hooking up a timing light to cyl 1 and shining it at the driver's side injector, then hook it to cylinder two and shine it at the passenger side injector. If the pattern looks like a piss stream and not a cone-ish fan, then you probably need to take them out and soak them in some berryman b12. Call me tomorrow after 5pm and we can talk more if you have more questions.

[KrazyKarl02]

The injectors appear to be working, they have a fan like spray, and I can see them kick on and off, but they are throwing a lot of fuel out. We tried to look for any uncapped vacuum leaks, but it was hard because Keystone was there..... I am betting on a regulator.

[stx4wheeler]

Fred thanks, I figured you would be wiped out from the show, but I will definately give you a shout tomorrow to talk through some stuff.


I did some searching and Colorado K-5 has a bunch of info. I havent seen someone with my exact problem, but most of the threads on running to rich seem to be tied to Coolant Temp Sensor, because if the sensor is bad or not reading correctly it will send the computer a signal saying that ambient temps are -40 degrees so the comp dumps tons of fuel to it to keep the a/f ratio correct.

Also, alot of people have O2 sensor problems as well. Im out of town this week for work in Corpus and so I am going top make a trip to a junkyard and pick up a handful of senors so that this weekend when I get back home I can start to throw some parts at it. Im also going to look at buying the cable to hook my laptop to view whats going on real time.

[stx4wheeler]

Changed the fuel pressure regulator, and the problem got worse. Had Fred and Ryno take a look while I was cranking it and the side injector was spraying it's arse off. So I pulled both injectors out and soaked them in carb cleaner for 4 hrs and now she purs like a kitten. The injector was stuck open.

[TdmayfieldIV]

Check engine light coming on after sustained highway driving. Missing and backfiring under slight load, going uphill keeping 70 mph. Water temp never gets above 195.

[stx4wheeler]

Electrical tape over the check engine light.

Sounds like a bad sensor.

[TdmayfieldIV]

That doesn't fix the backfiring

[KrazyKarl02]

That doesn't fix the backfiring

Ear plugs?

[stx4wheeler]

The coolant temp sensor is what ended up being my problem why it was running rich, but I'm not sure how yours is setup.

You work at a parts store replace one sensor at a time and return what doesn't fix the problem. I would try coolant temp first, tps, then O2 sensor.

Hopefully Flem or Fred might have a better idea.

[TdmayfieldIV]

Flem?

[robertf03]

what was the code?

[TdmayfieldIV]

let me check tomorrow. I didn't know you could do it with a paperclip.

http://tr6.danielsonfamily.org/TBI_15.htm

heres a list of tbi codes btw frick

[TdmayfieldIV]

12, 13, 59, 67, 75, 81, 82

[TdmayfieldIV]

DTC - 13 Oxygen sensor circuit open or no activity
DTC - 13 Left bank O2 sensor circuit open or no activity
DTC - 59 Trans fluid temp sensor circuit error (high voltage)
DTC - 67 A/C pressure sensor circuit error
DTC - 75 Digital EGR solenoid #1 circuit error
DTC - 82 3x Crankshaft position sensor circuit error

And I got a #81, which doesn't exist

[Fredo]

Sounds like a bad ecm/chip. How did you mount the computer?

[TdmayfieldIV]

Behind the glovebox. Suspended in zip ties.

[TdmayfieldIV]

I pulled the chip out (it had come loose) and put it back in. It runs fine now.

Found this on pirate. I'll be changing pumps to see if I can find more top end.

http://www.pirate4x4.com/forum/showthread.php?t=727927

[colman]

tbi doesn't like to much pressure iirc

[TdmayfieldIV]

So I unplugged the memcal and put the stock chip in and it ran like ****, then I put the burned chip in and it ran better and the check engine light went off and it's running less ****ty (i'm sure it will return).

So it is reading the chip. My next guess would be the 02 sensor. Maybe all of the codes I listed earlier were stored from the old truck it was in?

[TdmayfieldIV]

Starts up immediately
Idles ok, not too smooth
500-1000rpm seems about normal. good throttle response
1000-2000rpm Under load it stumbles and hesitates
2000-2200rpm seems to realize it's ****ing up and catches itself. Stops stumbling and runs normal
2200 rpm + Continues to run like ****

[Hot Pocket]

Invest in a 2bbl 2150 and run it on propane. There's a reason they call it fool injection :flipoff3:

[TdmayfieldIV]

You sir are an idiot.

[Fredo]

Starts up immediately
Idles ok, not too smooth
500-1000rpm seems about normal. good throttle response
1000-2000rpm Under load it stumbles and hesitates
2000-2200rpm seems to realize it's ****ing up and catches itself. Stops stumbling and runs normal
2200 rpm + Continues to run like ****

Sounds like you might have the distributor wired backwards to the ecm. Try flipping over the wiring on the circled plug below.

18944

[Fredo]

I'm stupid. I meant to circle this one. Check this pic.
18945

[TdmayfieldIV]

Thanks Fred ill try that

[Sharpe]

If you're good at something...

:flipoff2:


I'm stupid. I meant to circle this one. Check this pic.
18945

[TdmayfieldIV]

Fred was right. One of the wires came off the little posts on the icm. I haven't given it a full test drive but it seems to work fine now. I'm still wanting for more top end. It has always been lacking since I got rid of the carb. I think the timing curve is too shallow. This motor loves more advanced timing. In Colorado I had it at 13* advanced without pinging and it screamed. With the change in altitude I had to retard the timing.

[TdmayfieldIV]

****'s still ****ed. I have better symptoms now that I bought a tach.

It hates WOT. If its idling and I floor it it will stumble to 2500rpm then go
When driving i'll be cruising around and then the tach needle will bounce around a little and it will stumble, then it catches itself and goes.

Check engine light will come on after 5-10 minutes of driving

I have replaced the following things
-fuel pump
-strainer and filter
I blew out the lines with the air compressor too
-computer
-icm
-tps
-icm wiring
-icm ground (this has been an issue since the summer. It kept coming loose and shutting off. (that's what happened on the baja course btw)
-coil wiring (also has been an issue for a while)

This all started out of the blue while driving to alto, I was cruising at 60mph and the light came on and it started backfiring.

Flem believes it to be the memcal/chip, but i'm an idiot and forgot to order it. Maybe the chip is toast from the near fire mishap at katemcy. It seems like that's when I started having issues

I'm hoping flem will remember to burn me a new chip for clayton.

[Fredo]

You might want to check with him on that....I don't think he shines shoes no more.

[TdmayfieldIV]

That's unfortunate because my shoes can only be shined by very few people. They are rare shoes, so rare that people who normally would shine shoes that look similar will not shine these shoes because they don't know how to shine them. They fear that shining said shoes could result in even less shiny shoes, shoes that will not protect my feet from the ground anymore.

Being that I know nothing about my shoes and my shoes have an ignition problem I am going to get a megasquirt computer and remake the soles of my shoes myself. I think my new shoes will not control my ignition, as a msd 6al box will do that fine. My shoes will get a new distributor, ignition box, bad dood coil, all new wiring, megasquirt computer and then Maybe my shoes will help me run like a raped ape again.

http://www.diyautotune.com/tech_articles/megasquirt-carb-to-efi-part1-nova.htm

Maybe when my shoes work well again I can return to computer controlled ignition with the megasquirt shoe computer.

[Fredo]

You are such a fag. :flipoff2:

[JB]

That's unfortunate because my shoes can only be shined by very few people. They are rare shoes, so rare that people who normally would shine shoes that look similar will not shine these shoes because they don't know how to shine them. They fear that shining said shoes could result in even less shiny shoes, shoes that will not protect my feet from the ground anymore.

Being that I know nothing about my shoes and my shoes have an ignition problem I am going to get a megasquirt computer and remake the soles of my shoes myself. I think my new shoes will not control my ignition, as a msd 6al box will do that fine. My shoes will get a new distributor, ignition box, bad dood coil, all new wiring, megasquirt computer and then Maybe my shoes will help me run like a raped ape again.

http://www.diyautotune.com/tech_articles/megasquirt-carb-to-efi-part1-nova.htm

Maybe when my shoes work well again I can return to computer controlled ignition with the megasquirt shoe computer.

:laughing:

[TdmayfieldIV]

02 sensor fail...........i think it works again. For a week at least, until the next thing ****s up

[RCcola55]

I think you may owe some people an apology.

[BroncoJo]

I think you may owe some people an apology.

It's still ****... Who welds the o2 bung on and only leaves a 1/16 inch of clearance from the frame?

[robertf03]

probably needs motor mounts

sounds like you got it under control Travis

[BroncoJo]

Tommy won't listen to me.

http://i246.photobucket.com/albums/gg115/BroncoJo/IMAG0622.jpg

[RCcola55]

Lather rinse repeat

[Sparling]

I'll order him mounts at work tomorrow. He can put them on the bronco sunday.

[BroncoJo]

The mounts aren't bad.

[TdmayfieldIV]

I dont remember blaming anyone. I was just asking for help.

[85cj7]

I dont remember blaming anyone. I was just asking for help.

and you need lots of it. :flipoff2:

[TdmayfieldIV]

Replaced the 02 sensor. Check engine light didn't come back on for 1 day
Replaced Coolant temp sensor. Check engine light didn't come back on for 2 days

This is ****ing weird. Now it's back on and running ****ty again.

not that anyone's interested anymore after that mess

[Sparling]

Post up on a chevy tbi swap forum and maybe someone can help you figure it out.

[TdmayfieldIV]

From what i've been reading, the computer will go into "limp mode" and dump fuel and retard timing if it can't make sense of the sensor readings. So probably a wiring harness short.

[RCcola55]

Or massive pre o2 exhaust leak....

[sasquatch]

mine had been running like **** lately. it would start up and run fine, but under load it would stumble/miss/act like it wasn't getting fuel. once i determined it wasn't out of gas, i thought the paper in the fuel filter had come loose and was plugging up. replaced, no fixy. fuel pressure is 9 psi according to the gauge, kinda low. before i fukt with the fuel pumps, i thought i'd look at the cheap tune up stuff. warrantied out my wires since battery acid ate parts of them, new cap, cleaned rotor, etc. pulled out the plugs to see if they were fouled, they looked great. i replaced them when i did tbi. still stumbled. jacked with a few other things and checked for loose wires. decided to pull plugs again to replace with new ones. this one crumbled into pieces this time when i pulled it out of the socket. probably was leaking spark under load.














19189

new plugs in. runs great again. least i didn't fag out and put a carb back on it. :flipoff2:

[TdmayfieldIV]

So it wasn't a tbi problem then was it?

My motorcraft 2bbl runs better than tbi on it's best day.

[DRAGOONRANCH]

So it wasn't a tbi problem then was it?

My motorcraft 2bbl runs better than tbi on it's best day.

Hook line and sinker.......