This vid is a 91' Formula. Its had a motor swap and wont work right now. Its a 9.3 c/r stock 350 with completley stock lb9 everything. Computer, injectors, etc. It wont go above @1500 rpm. With #22 injectors it did the same thing and now has #19 inj. again. The Fuel pressure is at 43psi steady. Any suggestions.





91' Formula 350

 

What exactly does it do when you fllor the accellerator??

 

bogs down and dies. most sensors are new and timing has been played with several times.

 

Sorry i left this out. The cam is aftermarket. Here are the specs...

FYI - XR269HR-12 - .495 / .503 Lift & 218 / 224 duration(@.050) [advertised:269/276] – 112’ Lobe Sep(1500-5500)

 

Interesting. That cam sounds a little meaty and you have a speed density car. Did you have a chip burned for this car yet? A chip burn is a must on SD cars with cams. I would bet the Map readings are why off. Do you have any data logs of the car from diagonstic software?

 

is the fuel pressure steady when it starts to die? can you lightly push the throttle and let it ramp up? try disconnecting the MAP sensor and see if it will rev up in the 'limp home mode'
does it throw any codes?
is the chip in the car originally from the 91 with a 305?

 

egr

 

Temp was warm....... Looks like higher than stock.

 

you need to get a 350 memcal and the 22# injectors in there at the least. you may have to get a chip burned for that cam since it's SD.

 

sounds like u need custom tuning so the car will run right with that cam. speed density is very sensitive to cam changes.

 

I dont believe the prom is the answer, Ive ran a ZZ-9 cam in a 350, with 19 lb. injectors, and a stock 305 prom. My car never acted like that. I would check all the obvious. Fuel filter, pump etc. Somthing is wrong and its not the calibration.

 

Fuel pressure is acting fine.. Were taking the EGR valve off friday. The prom is a stock lb9 auto prom and it has #19 injectors. It does the same thing with #22 injectors. Thanks for all the help guys.

 

will be borrowing a data logger with in a week or so.

 

I wonder if the ignition module is cutting out.

 

was it speed density?

 

Always think..spark/air/fuel.

Fuel pressure = ? Watch the fuel psi when the car is running and dying.

Spark, make sure you are getting spark

Possible vacume leaks?


For some reason, I suspect the TPS sensor. Have you ran a code test on the car? Try to unplug the tps sensor and see what happnes. Also, try adjusting the tps sensor, or at least checking the voltages it's showing @ WOT.

It could be a bad map sensor too. I think the map sensor code is a code 33 or 34, the tps sensor is a 22...I think?

 

It threw a TPS , IAC, and 02 code and all of the have been replaced. Prolly will change the map also.

 

I would suspect a tps sensor, did you adjust the TPS sensor?? You can not just throw the tps sensor on, you need to adjust it to work correctly. If you have adjusted BOTH tps and IAC, I would check the wring harnes.

 

if it's sd, the ecm automatically adjusts it for you. no adjustment required.

 

Sometimes multiple codes could be an ECM problem...After you replaced the sensors, I assume the codes went away? Just to eliminate the FPR, see if you can smell fuel in the vacuum hose.

 

Do i have to adjust the TPS on a SD motor? Im fixing to swap ecm's out of my 91' GTA. Its has a custom Hypercrap chip so maybe that'll compensate a hair bit for the larger bore. AFPR seem fine. The timing was adjusted a few weeks ago. Just the other night we checked it again and it was WaY far retarded. Could the dist. gear (or soemthing relative) be a possible cause?

 

O.k. the timing should not have moved. (unless you did not bolt down the dist. all the way). Sounds like we are getting close to the problem area. It is very common for these cars to have problems with the distributor. I just replaced mine with the MSD direct replacement. My car starting going nuts and I could not figure it out. Turned out the mag. pickup in the distributor was slowly falling and causing the car to throw the timing all over the place.

Let's try this, put the timing light on one of the ign. wires and rev up the car. Watch the pulses on the light and see if they have any irractic flashing.

Also, pull the distributor cap off and inspect the mag pickup and ignition module for excessive corrision. If the mag pickup looks like hell then I would consider replacing the distributor.

 

I would verify the voltage after you install the tps sensor! Never hurts to check!!!

 

How does the ECM adjust a TPS??? The IAC I could see, but not the TPS...

 

Burnout 88'. That does happen. WHat do you recommend?

 

i would personally just rather use a 85-89 adjustable TPS on a SD setup and adjust myself. not to mention it's cheaper than the sd TPS.

 

[QUOTE]Originally posted by SLP IROC-Z



yes it is

 

We pulled the distributor and the gears were worn on it real bad. Put in a new distributor and now it will idle and also rev up to whatever RPM we want it to. The only problem now is that when we try and put it in gear and drive it, it wants to die. Tried to adjust the timing again and cant even find the timing mark now. Going to try and locate TDC now and then make new mark and adjust the timing again. Were one step further now. Just want to thank everyone for there help.

 

I have been off line for a couple of days, But it sounds like you almost have this solved. What brand distributor did you put in? Stock rebuild or MSD, Accel, etc.

Also, when you are setting the timing are you putting the Electronic Spark Timing (EST) in bypass mode. Usually, to bypass it you have to disconnect a tan wire with black stripe on the passenger side loom.

Also, I have done this to help locate the timing mark on the balancer. Jack up the car and have a friend bump the starter without starting the car. (disconnect the ignition to prevent from starting, usually unplugging the two connectors at the coil should do the trick). Then watch the balancer spin around in half turns and you should eventally see the timing mark pass buy. It is a grooved line in the balancer. Once you find it, mark it with some white paint. This should help you locate tdc.

What timing light are you using an adjustable digital or I hope one with at least the adjustable **** on the back. It is much easier to set timing with this type of light when you lose your orginal mark.

 

Got it fixed. Bought a programmer and adjusted a few paremeters. Map, IAC, etc. Going good now. Thanks a whole lot for all your help guys.

 

It doesn't it resets it's zero references for the TPS, and IAC at startup (if you step on the gas pedal while cranking the ECM uses the last TPS zero reference.)

Each time the engine is started and then the ignition is "OFF" the ECM will reset the IAC valve. This is done by sending enough counts to seat the valve because the ECM has no feedback circuit (for adjustment) to know if, or at what count the valve pintle stopped moving. The fully seated valve is the ECM's zero reference.