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TBI swap completed, now onto the troubleshooting

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samsterman99

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Got my TBI Swapped in. The chip is for a manual transmission, so I plan on making my 700r4 lockup internally with the wiring. I have everything wired up except for the crank sensor (seems to not be necessary for the moment), the P/N switch (doesnt matter since its a manual), the EGR and the other emissions stuff.
Starts up quick, idles @ 1300 and then about 800 when warm. No codes until at high way speeds and light throttle, code goes on and off, I assume its the EGR code being set.
One problem I have is with the Idle, IAC, and setting base idle. I have jumpered the diagnostic terminals, unhokked the IAC after 45 sec, and then started the car and the idle is at 2500 RPM's.... How is this possible?
The only other problem is at low RPM's and about 1/10th throttle off idle, the car seems to go flat and bog, and after 2 seconds the car gets back on its feet and runs fine. Or if I increase the throttle the problem goes away.
I sprayed ether around the TBI base gasket and the car died and stumbeled. So I assume I have a vaccum leak and need to get that sorted out first.
Could all these problems be connected to a vaccum leak? It doesnt seem like a major leak, but I could be wrong.
Also, is leaving the manual EEprom in there a bad idea? Or will it just run fine since I am not going to use the ECU to make the lockup function.
 
Yes all those problems could be caused by the vacuum leak. Replace the throttle body base gasket and then go threw that idle reset procedure again.
 
I will get to that hopefully tomorrow, its a brand new gasket, but I think my bolts are bottoming out through the adapter plate and I will need a washer or 2.
 
samsterman99 said:
I will get to that hopefully tomorrow, its a brand new gasket, but I think my bolts are bottoming out through the adapter plate and I will need a washer or 2.
Click to expand...
That is a very common problem with adapters and stock TBI mounting bolts.

1. Crank sensor?
2. What ECM are you using?
3. Better yet what motor etc...?

Code at highway speed is probably Code 32 which is an EGR test failed. EGR is not a bad thing unless this is built engine in a race car. It does not hurt HP at all and increases MPG.

Manual chip in the ECM can be changed out to Auto very easy. The bin file between manual and auto are very different. Just swap in a new chip for auto and then you'll have your torque converter lockup handled as well. Depends on number 2 above.

Don't know how you got to 2500 RPM but RPM will rise with ALDL A and B still crossed when doing IAC reset and Min Air Adjustment. But not that high.

1/10th throttle issue could easily be the vacuum leak or a faulty TPS sensor. To check TPS sensor use a digital volt meter and watch reading at idle should be about .54 volts to wide open about 4.5-8 volts with a smooth slow swing. No jumps or glitches. If you see a jump or glitch around the 1/10th throttle you will know the TPS is faulty.
 
The crank sensor is the 12v hot wire only in crank. I believe it ritches the mixture for a quick startup. But mine starts fine without it.
It the 7747 ECM,
My truck has the stock 1986 engine that came with the ccc q jet, only addition is a car back exhaust and a gutted (missing) cat converter.
I actually just blew the solenoid in my tranny and was just goin to wire it for 4th gear lockup and avoid the ECM control since mine doesn't seem to match the efi wiring. I also can't find a park/neutral switch so the manual chip isn't too bad at the moment.
 
samsterman99 said:
The only other problem is at low RPM's and about 1/10th throttle off idle, the car seems to go flat and bog, and after 2 seconds the car gets back on its feet and runs fine. Or if I increase the throttle the problem goes away.
Click to expand...
I had a similar problem and needed to enrichen the accelerator pump.

Problem is you have a vacuum leak that needs to be fixed before you can diagnose anything else.
 
Ok, I fixxed the vaccum leak, and did a little troubleshooting.
This problem only happens when the engine is at operating temp. During warm up the engine has perfect manners and is not stalling. It also feels like it has a lot more power and no flat spots. Bad O2 sensor? Anything else besides the tune in the chip that could show up at operating temp?
 
Could be lots of things?

What is the fuel Pressure?

Timing set?

Check for stored trouble codes?

Scan Tool will tell you what everything is doing?
 
samsterman99 said:
Ok, I fixxed the vaccum leak, and did a little troubleshooting.
This problem only happens when the engine is at operating temp. During warm up the engine has perfect manners and is not stalling. It also feels like it has a lot more power and no flat spots. Bad O2 sensor? Anything else besides the tune in the chip that could show up at operating temp?
Click to expand...

What engine is this? Do you have the ALDL cable? My motor runs a little similiar when cool it runs excellent. Once hot it will detonate much easier and the timing is usually backed off once the engine reaches operating temp. I've gotten to the point I don't think tuning by ALDL cable is going to help anymore and will need to get it on a dyno.

Also what tune are you trying to run on this thing a stock tune? Need way more info.
 
nsxxtreme said:
What engine is this? Do you have the ALDL cable? My motor runs a little similiar when cool it runs excellent. Once hot it will detonate much easier and the timing is usually backed off once the engine reaches operating temp. I've gotten to the point I don't think tuning by ALDL cable is going to help anymore and will need to get it on a dyno.

Also what tune are you trying to run on this thing a stock tune? Need way more info.
Click to expand...
This is a Stock 1986 350, 180K on the odo, and the only modification is the cat has been removed and a magnaflow 3 inch muffler. I got the TBI from "stomis" a member on here and I have no clue what tune it has on it. I was going to order a stock chip and see if that helped me out. But I think my next investment is a aldl cable to see what is really going on. The timing was set at 0 with the est bypass,
 
nsxxtreme said:
My motor runs a little similar when cool it runs excellent. Once hot it will detonate much easier and the timing is usually backed off once the engine reaches operating temp. I've gotten to the point I don't think tuning by ALDL cable is going to help anymore and will need to get it on a dyno.
Click to expand...
What makes you think a dyno is going to help that issue? Most dyno time is spent for WOT. At $150 an hour if your lucky... that's all it's needed for. All the other tuning is done driving. Most dyno owners will not let you use it for drivability and sit there and drive for hours and wear out their machines. So you get maybe 4 WOT runs in an hour if your prepared to tune in between.

You have problems once warmed up? But not while warming up? Warming up is adding fuel for choke. So are you lacking fuel when warmed up? Another issue when warmed up is EGR starts working. If you don't have one and it's not disabled PROPERLY well then your adding spark when the EGR is operating and your ECM does not know it's not there. Many guys just turn off EGR error code, that does not disable EGR. Do you have an EGR?

Your set up to data log right? So get some good software to data log and we can find the issue. TunerPro RT !!!

What ECM? We better go back to your thread after this...



samsterman99 said:
This is a Stock 1986 350, 180K on the odo, and the only modification is the cat has been removed and a magnaflow 3 inch muffler. I got the TBI from "stomis" a member on here and I have no clue what tune it has on it. I was going to order a stock chip and see if that helped me out. But I think my next investment is a aldl cable to see what is really going on. The timing was set at 0 with the est bypass,
Click to expand...
Getting a cable and TunerPro software is going to be your best friend! It will not only adjust your bin file (then need burner to write new chip) but has a programmer built in to burn the file to chip with Moates Burn 2 or AutoProm.

It is also a data logger and scan tool. Will read codes stored in ECM. Data log shows way more stuff than WinALDL in a way better format to see what's happening and exporting data to use spreadsheet to fix your fueling (VE) tables.

Like said above EGR can be an issue, do you have one?
 
no, i have the carb intake and a block off plate installed. can the advance and all egr functions be disabled in a custom burn?
 
excellent. I think my cheapest and most effective option at this point is to get the right chip in there and see where that lands me. I will report back when I get it and install it
 
samsterman99 said:
The crank sensor is the 12v hot wire only in crank. I believe it ritches the mixture for a quick startup. But mine starts fine without it.
It the 7747 ECM,
My truck has the stock 1986 engine that came with the ccc q jet, only addition is a car back exhaust and a gutted (missing) cat converter.
I actually just blew the solenoid in my tranny and was just goin to wire it for 4th gear lockup and avoid the ECM control since mine doesn't seem to match the efi wiring. I also can't find a park/neutral switch so the manual chip isn't too bad at the moment.
Click to expand...
Crank wire is a good thing and simple one wire to post on solenoid that gets power when key is in crank position.

Manual bin does not have P/N Switch wire.

Your truck should have VSS behind speedo I think to DRAC box and should be wired into your ECM. Again a good thing.

Your in CA? Your going to need EGR to pass emissions, actually, legally you will not pass emissions with a TBI conversion unless it has a CARB number. So you need to tell them it is a 1987 Chevy engine swap and you will have to pass 1987 Chevy Truck emissions test.
 
Just wanted to update this with a little bit of closure:
Got all the swap working with TCC lockup and a new chip installed. It works AWESOME off road, leaps and bounds better than my q-jet. I was able to idle down a bumpy, steep drop off and not have it stall out on me. Also climbing is very smooth. Oh, gas mileage went from 8mpg to 13 mpg. So In three months i will have made my money back in gas savings!
The downside is I still have a little surge when the motor is warm at idle, and i need to put on my tbi intake manifold since I am still running an adapter to the smaller bores of the q jet intake, and it is restrictive. It does have less power than my carb did, but I think that is due to the intake problems.
Thanks again to everyone for the help!
 
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