I got it running this morning, but now it won't start. I got the MAP table setup close, but the acceleration enrichment is basically non-existent. When it was running and I step on the gas even at a relatively usual rate the engine died like it had no fuel. I checked the TPS voltage manually at the wires, but I got some wierd readings. Should they be like GM(.5-4.5 or so) readings or will they be totally different?

Now when I try to start it it fires up for a second and dies like the initial start enrichment works, but maybe the TPS isn't taking over after that? Could it be a bad TPS? It does this every time now - fires up for a second and dies.

This is so frustrating!

Thanks

------------------
88 firebird formula
350 Vortec, Accel Pro-Ram MPFI
214int/224exh, .471int/.491exh
Edelbrock headers
T56 - SIX-speed
open 3.73's
3 inch Flowmaster catback
I love pissing those LS1's off

Old time with TBI - 13.9 @103mph, 2.6 60ft

My Formula

 

The first thing that comes to mind is a possible fuel pump or fuel delivery problem. Was everything upgraded? What kind of pressure? Second thing is the timing.

Yes, the TPS should read about .5V to 4.5V.

Sweet looking Formula, BTW.

[This message has been edited by RCR (edited October 29, 2001).]

 

Very clean looking car. I'm sure you'll get it running good soon. Sounds like a bad fuel pump to me BTW.

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1986 IROC, fully loaded, Mini Ram'd 383, Art Carr 700R4, Accel DFI, 12 bolt rear, etc, etc......

 

The fuel pump seems to be working fine. It primes and when the engine quits running the fuel pump is still running a second or so after the engine quits.

TPS seems to be working wierd. When I ground each of the wires - one is dead(TPS ground), one reads 2.4 volts steady, and one reads 2.4 volts going down to .5 volts as I open the throttle. Seems backwards and a low voltage to me.

It seems that when I return the key to "run" there is no power to the coil maybe or something isn't getting power in the "run" position because I'm almost 100% positive that the fuel pump is running fine. It has all new wiring and is independent.

Can a bad module cause no spark in the "run" position?

Unfortunately I'va had to go back to college for the week and can't get back to my car until friday . I'll keep you updated. Thanks for the compliments!!

 

sounds like some wires are switched somewhere

when the throttle blade is CLOSED it should read about .5 volts

when the throttle blade is at WOT is should read about 2.4 volts

 

Hmmmm.... interesting.

89ProchargedROC - Do you have one of these systems? Are you positive that it should read about 2.4 at WOT? Because if your right then I don't have to worry about getting a new TPS. I'll just switch the wires. Man I hope you're right! Should solve my abscence of acceleration enrichment right?!?!?

Hopefully that just leaves one problem - no start in "run" position. I think that's distributor related. Possibly the module?

Thanks!

 

Let me throw this out there then since it comes to mind...

when I first started up the car it was sooooooo rich!!! Like, I almost killed the dog!! After I got it back to a normal level at idle the first column(top to bottom) on my MAP table ranged from about 10 - 39 which was about 1/3 of the preprogrammed values. Do you think the TPS was showing WOT causing the computer to shoot out the original 130 values at the bottom left of the chart? Then I would assume that when I stepped on the gas the computer would think I was going back to idle causing abosulutely no pump shot and less fuel because of less throttle position. Man, this would solve a lot of my problems.

Now if I can just get it to start...

[This message has been edited by Birmass (edited October 29, 2001).]

[This message has been edited by Birmass (edited October 29, 2001).]

 

What size injectors are you running and how many cells have a value of less than 15? DFI cannot accurately control the injectors below a map cell value of 15. Idle and low speed drivability sucks the lower your map cell values.

 

Yeah, anything below 28 is not really good. Here's the thing. The original table had values in the far left column from about 37-130(top to bottom) which converts to about 2.3-8.15 milliseconds. This is what SHOULD be about right for my car with 30# injectors, but was running incredibly rich!! While the engine was running at idle and no load the map table was reading 1kpa. 1kpa at idle was giving 8.15 milliseconds of fuel to an engine with absolutely no load(that's a lot)!!! What i did when I first saw this was to multiply the whole fuel map to get the engine running the right A/F ratio. This means I had to take the bottom left hand corner of the table all the way down to about 37(2.3 milliseconds). Which sent the low load readings to 10. Here's what I think was causing this. If the TPS was backwards idle would be WOT thus negating MAP readings and switching to WOT mode. This forced the fuel table to control in the 1kpa range of the table but with the engine running at idle and no load. Basically, the computer has a backwards TPS. Idle = WOT. WOT causes a default to 1kpa readings on the fuel map and gives a fuel mixture for idle at 1 kpa(130's range- 8.15 milliseconds). Make sense?? I hope it does because this could solve a lot.

Edit - To clarify I NEVER saw the car idle at ANYTHING less than 1 kpa of load. No good.

[This message has been edited by Birmass (edited October 29, 2001).]

 

Birmass,Myabe I can help.With my System,Tec 2.I can set my voltage min and max readings.Every TPs will read different,I had ones that read .80 at closed throttle,and have one now that reads 1.31 at closed throttle.I can correct for this in my software,And I think you can too.Voltage should alway go from low to high,if not,and goes opposite you have wires switched.Map senso is a 0-5 volt sensor.If you are running a 2 bar,you should see about 1.2-1.5v at idle.On my car I run a 1.5 ms pulse width at idle.It varies on each car,I just have a problem with idling cause of my 50lb injectors.But you have ing a 8ms pulsewidth at idle is way to rich,I dont know how it would run.Definatly cheack your wiring

P.S. Before anything else warm up car and dissconect the idle air control motor,and cover the idle bypass holes in tb,and set the idle.Well before any of this make sure wiring is correct.

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Check out my Hompage,or the beginnings of one.355 dynoed at 400HP at 5800RPM & 410LBFT of TQ,on Motorhttp://www.procharged89z.cz28.com/index.html

[This message has been edited by PROCHARGED89Z (edited October 30, 2001).]

 

Yeah, I'm gonna rewire the TPS that Accel did backwards and check everything then. I think thats screwing everything up. I'll keep the post updated. Thanks for the help!!!


------------------
88 firebird formula
350 Vortec, Accel Pro-Ram MPFI
214int/224exh, .471int/.491exh
Edelbrock headers
T56 - SIX-speed
open 3.73's
3 inch Flowmaster catback
I love pissing those LS1's off

Old time with TBI - 13.9 @103mph, 2.6 60ft

My Formula

 

well it doesn't HAVE TO read 2.4v at WOT....it should just RISE linearally from closed to WOT the voltage that is...TPS voltage will vary

also if the module was bad...the car wouldn't start

the main thing the module does is when the car is cranking it senses this and tells the computer to ground out the injectors to give the motor fuel to fire...otherwise it wont tell computer to ground, and then no fuel, and then no start

 

Car still won't ****ing start!! WTF!!! I'm about to ****ing torch it!! I have never been so frustrated in my life...

It starts for a second and just dies. It will do this every time. I turn the key on, the fuel pump primes and it fires right up but then dies in a second. I got a new module. The pump is running when the car fires up and the coil is getting 12 volts all the time. I swapped coils and it does the same thing. I can communicate with the ECU through a laptop fine.

I have NO ****ing clue as to where to start. I'm so pissed. This will be ****ing week 6 without my ****ing car!!! **** **** ****!!!

------------------
88 firebird formula
350 Vortec, Accel Pro-Ram MPFI
214int/224exh, .471int/.491exh
Edelbrock headers
T56 - SIX-speed
open 3.73's
3 inch Flowmaster catback
I love pissing those LS1's off

Old time with TBI - 13.9 @103mph, 2.6 60ft

My Formula

 

Alright, it's running now!! Thank *** !!!!

Somehow when I changed the fuel maps to lean out the idle it worked fine for a few starts, but then became too lean to keep the engine going when I tried to start it later. I hadn't changed anything in teh computer between the time it started to the time it wouldn't start so I didn't think there was any possible way it would be too lean to start. Oh well...

I need to make sure I have 30# injectors though just in case they gave me larger injectors on accident. If I can't get the mixture down I may need to change them. How can I tell what injectors they are? Any numbers on them?

Also, do you guys think 30# injectors are too big for my engine? Should be around 360 HP, 400lbs torque.

Thanks!

 

I dont think it will matter what size injectors you have since you have total control of their pulse widths.

The 30# SVO injectors are red tops. Blue is 24#. Not sure on others...

Good luck. Sounds like you are getting there.

I had a similar situation with my speed pro except it started and was too lean. I had to keep on enrichening the start up to get it to start and run. Then, I have a seperate table for VE. It surged a lot until I adjusted the cells it was using for idle. Surging is lean.

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-86 IROC

-=ICON Motorsports=-

 

Another question for you guys.

For Accel DFI does anyone know how to adjust the value of the TPS in the computer. In Calmap their is a view screen that is basically like a scanner. It shows all of the sensors and their output. My TPS only goes to 40% when I have the throttle open all the way.

Thanks!

I'm getting closer, but it still doesn't seem like I'm getting ANY TPS enrichment. Could be because it's only showing 40% at WOT though.

 

If your TPS is at 2.4V @ WOT, then that would explain a reading of 40%. The TPS for the DFI should read similar to the stock values, 0.5 to 4.5V, or so. I did have a problem at a customer recently where they miswired a similar type of sensor. They connected the wiper wire to the positive, and were sensing from the hi side of the sensor. Made for some screwy readings.

 

Also, to answer your question, the only adjustment on the DFI for the TPS is zeroing it. You would have the throttle blades closed and adjust the sensor position until the screen value was zero.

 

CRAP!!!

I don't seem to have a 5 volt reference to any of my sensors. It only goes to about 2.4 volts. Without the engine running my MAP sensor reads .56 . I may have shorted the 5 volt reference out when I was checking the TPS voltage a few weeks ago but didn't realize till now. A tech person at Accel said they could look at it. Does anyone know if this is fixable. Those little boxes are expensive!!

------------------
88 firebird formula
350 Vortec, Accel Pro-Ram MPFI
214int/224exh, .471int/.491exh
Edelbrock headers
T56 - SIX-speed
open 3.73's
3 inch Flowmaster catback
I love pissing those LS1's off

Old time with TBI - 13.9 @103mph, 2.6 60ft

My Formula

 

Well, if you were closer, I'd love to look at it for you. I wouldn't mind seing what's inside. It's probably something easy to fix, it's just a matter of knowing what to look for. My guess would be that a 5V regulator was smoked.

 

RCR - That sounds about right actually. I'm glad you said that because I was thinking it would be more complicated than that, but you're probrably right.

I sent it out to them today. They seemed to be pretty optimistic about fixing it. If it's just a regulator I don't see how it could be that big a deal. Thanks for easing my mind a little.