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ECM keeps retarding timeing

Old Jul 24, 2004 | 10:05 AM
  #1  
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From: NH
Car: 88 I-ROC
Engine: 355 TPI
Transmission: BW T5
ECM keeps retarding timeing

Good day to you all.... have a 88 TPI 350 that will not accept my 6' advance i have put in it(dist turn)...the vehicle lays down while opening throttle...no popping....but it doesn't advance like it should while opening throttle up @ the same time....she does advance and rise...but very slowly...I'm holding the throttle open to about 3,000 RPM but the ECM OR something retards the timeing right away and pulls the engine right back down......man..does this bite on accel...lol.....she just lays down.I have checked fuel psi..and its good (43-45 vac connected)---(set to 48 on regulator w/vac disconnected and plugged). I can't seem to nail this one...knock sensor on the fritz??? maybe egr selenoid??? I hear no knock...no pinging either....tapped the MAF...no stumble there...no codes to boot. any one else run into this??? I even reset min idle..TPS voltage..etc. cleaned IAC
What does one do in this situation????

Thanks for your time andHope you can help me out

Brent
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Old Jul 24, 2004 | 12:11 PM
  #2  
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From: clearwater
Car: trans-am
Engine: tpi
Helpful info would: Did the car run fine before you made any changes? What changes did you make before it started running bad? Did you pull the distributor out, or did you just turn it a little? Did you remove any spark plug wires?
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Old Jul 24, 2004 | 12:39 PM
  #3  
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From: Grand Rapids, MI
Car: Z28
Engine: Sb2.2 406
Transmission: Jerico 4 speed
Axle/Gears: Ford 9" 3.60
Unplug the tan ESC wire from the firewall area, by the heater box and reset the timing again.
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Old Jul 24, 2004 | 12:48 PM
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From: NH
Car: 88 I-ROC
Engine: 355 TPI
Transmission: BW T5
hello....thanks for getting back to me.here's what I did.


1. installed an Accell external coil..to replace original one...it was an "upgrade" ..it was the "super coil"

how do you test it??? ...I have a volt meter I of course not thinking ..threw the old coil out. I did this test today on my EGR valve..see if this makes sense to you.


engine off...hooked up vac gauge to valve and pulled it open no problem....I then STARTED CAR with vac guage still connected and tried to pull the valve open again...the valve would not pull open on my vac guage..(would stay @ 0..would not climb)..i would pump..pump...pump...nothing..which tells me the valve wasn't opening...this normal ??? it will open with vac guage when vehicle is off.

I wonder if its timeing or a sensor.....let me know what you think.

thanks again

Brent
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Old Jul 24, 2004 | 12:52 PM
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From: NH
Car: 88 I-ROC
Engine: 355 TPI
Transmission: BW T5
I have reset the timeing again to 6' (4 th time) shut vehicle off...plug wire back in..start car....idles great...pull some throttle on it...it lays down....when i snap the throttle...the motor should snap aswell...it does not,It has to play catch up.
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Old Jul 24, 2004 | 11:11 PM
  #6  
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From: Cypress, California
Car: 1989 GTA
Engine: 369 TPI
Transmission: 4L60E
Axle/Gears: 3.70 Nine Bolt
Talking to a gentleman today who had a similiar problem. His turned out to be the EGR valve. Allen
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Old Jul 25, 2004 | 01:12 AM
  #7  
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From: Houston, Texas
Car: 88' IROCZ
Engine: 388 TPI Motown 350 Race block
Transmission: 700R4
Axle/Gears: 2.77
If you're sure there's nothing wrong with the EGR valve, then check the EGR solenoid.

Let me know if you need the EGR Diagnostic Flow Chart.
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Old Jul 25, 2004 | 07:47 AM
  #8  
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From: NH
Car: 88 I-ROC
Engine: 355 TPI
Transmission: BW T5
well...the fact that the valve will open with a VAC guage when the car is off....and not open when the car is running..sounds screwy to me...like i said in the earlier post.....I'll pull 10+and climbing when the car is off(Valve does open btw)...but when its idleing...I can't pull zip...pump...pump...pump.....can't get any reading on my VAC guage.just doesn't make sense to me. I mean..what would cause the EGR valve NOT to open when idleing,when your "pulling it open" with a VAC guage,but WILL open with VAC guage when vehicle is off.

I did notice that as I open up throttle..I can feel VAC from the hose from the selenoid TO the EGR..but not @ idle.I would assume seleniod is doing its job???

YES......I would like that flow chart you mentioned.

thanks a bunch

Brent rndsout@comcast.net <-----(for chart)
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Old Jul 25, 2004 | 10:07 AM
  #9  
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From: Lincoln, NE
Car: 1988 GTA
Engine: 350 TPI
Transmission: TH350
What about your TPS sensor? Is there anyway that it came unhooked or it could be faulty. Worth a shot. My car did the same thing when I forget to plug it back in.
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Old Jul 25, 2004 | 12:06 PM
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From: NH
Car: 88 I-ROC
Engine: 355 TPI
Transmission: BW T5
I checked that too.its hooked up and set @ 0.0560 smooth rool out to WOT @ 4.00
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Old Jul 25, 2004 | 12:25 PM
  #11  
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From: NH
Car: 88 I-ROC
Engine: 355 TPI
Transmission: BW T5
make that 0.540
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Old Jul 25, 2004 | 11:53 PM
  #12  
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From: Houston, Texas
Car: 88' IROCZ
Engine: 388 TPI Motown 350 Race block
Transmission: 700R4
Axle/Gears: 2.77
Originally posted by 88355
I checked that too.its hooked up and set @ 0.0560 smooth rool out to WOT @ 4.00
4.0v seems rather low, should be 4.5-5v. Throttle response increases with the voltage span (4.00-.054=3.46v versus 5.00-.054=4.46v, a full volt difference.) Even if you don't get 5v you still want it to be 4.5v, or higher.
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Old Jul 26, 2004 | 12:03 AM
  #13  
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From: Macedonia ,OH
Car: Formula
Engine: 6.0 LSX
Transmission: 4L60E
Axle/Gears: 9 Bolt 3:27
ESC Module? The KS tells that to retard timing and it does that. Could be your problem
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Old Jul 26, 2004 | 12:45 AM
  #14  
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From: Houston, Texas
Car: 88' IROCZ
Engine: 388 TPI Motown 350 Race block
Transmission: 700R4
Axle/Gears: 2.77
Originally posted by Mkos1980
ESC Module? The KS tells that to retard timing and it does that. Could be your problem
This one gets my vote. Maybe bad KS some are know to be very sensitive.
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Old Jul 26, 2004 | 04:27 PM
  #15  
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From: NH
Car: 88 I-ROC
Engine: 355 TPI
Transmission: BW T5
Hmmm...yes...bd KS was what i was thinking too...."something is telling it to retard...the KS..would do that I beleive.


will check into the chart Garcia sent me...thanks bud.that has been fired out of my printer :>) looks great and easy to follow.


and thanks too all again for the help.I have some diag work to do...I'll let you know the results...hope the news will be good.


thanks


Brent
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Old Jul 26, 2004 | 07:31 PM
  #16  
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From: NH
Car: 88 I-ROC
Engine: 355 TPI
Transmission: BW T5
I have done the flow chart I recieved from RGarcia..and my EGR system IS GOOD...all tests went clean,and green as instructed per flow chart IE...EGR operation..selenoid operation...etc.

I'm going to back track to the coil install..i had faith in it ..who wouldn't,after all its a "NEW" part right??? well I'd like to make sure its good, so how do you test it???..its a Accell "super coil" external type.I wonder if it is putting out the power to match the RPM requirment. (weak)Then again..wonder if its too much for my Dist and cooked it.


what do you guys think???


Brent
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Old Jul 26, 2004 | 10:41 PM
  #17  
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From: Houston, Texas
Car: 88' IROCZ
Engine: 388 TPI Motown 350 Race block
Transmission: 700R4
Axle/Gears: 2.77
What about your grounds?

I use battery cable to ground the intake, heads, and block to the frame on both sides. This may be an overkill, but I've run into many problems with faulty grounds.
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Old Jul 27, 2004 | 08:51 AM
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From: Wichita, KS
Car: 88 Trans Am GTA
Engine: 5.1L Gen III
Transmission: T56
Axle/Gears: 3.70
I don't want to insult your intelligence or car skills, but it sounds like the car isn't getting any advance at all. I'd check all your connections to thec coil and distributor. I think the distributor still has some mechanical advance, but its not enough to keep any engine happy.
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Old Aug 6, 2004 | 02:05 PM
  #19  
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From: NH
Car: 88 I-ROC
Engine: 355 TPI
Transmission: BW T5
Well heres the update so far......I purchased a new distributer(old one was looking ill @pick-up coil wires) and a new OEM coil....they are both installed....now I'm told I can't run my GEAR DRIVE with this motor...I'm so sorry about not telling you guys...I didn't know....this is my first build up of this motor,thaught i was doing awesome...yeah right!!! now i feel like a real DUMB #SS.after reading on and on...gear drive is a no no. I have since purchased a timeing set and now i have an issue with installing block protecting shim kit behind the cam sprocket..for the block i have in the car is NOT a OEM ROLLER CAM block..there is no thrust plate bolt holes.I also trying to find a larger cam button that fits the larger hole in this timeing set(the gear drive hole was a perfect diameter for the button..now button "floats around" in new sprocket. looking for advice on how to install the "block protector's" for they can't just sit behind the sprocket can they??? how do they "sit" also looking for a larger cam button..these exsist???


thanks for your time and sorry for being a boob...I'm still learning and hope you undertand.

Brent
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Old Aug 7, 2004 | 02:11 AM
  #20  
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From: Houston, Texas
Car: 88' IROCZ
Engine: 388 TPI Motown 350 Race block
Transmission: 700R4
Axle/Gears: 2.77
The cam button should fit in the center hole of the timing gear, the block protection kit requires machining the back face of the time gear ( machining specs should have been included in the kit.) If the cam is walking you may experience timing flutter (timing advances 3 or more degrees instead of smoothly.)

Did you check for cam end play? Did it require shimming?
Attached Thumbnails ECM keeps retarding timeing-timinggear.jpg  
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Old Aug 7, 2004 | 04:18 PM
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From: NH
Car: 88 I-ROC
Engine: 355 TPI
Transmission: BW T5
I have no idea yet as to how much end play i have....I need to first machine the cam sprocket for the "protector" kit...no machineing specs cam with the timeing set (summit SUM-G6600)

I need to correctly install kit behind sprocket first..then I can check for end play.I'm going to need a larger diameter cam button than I had with my gear drive any how.The new cam sprocket has a center hole of .878 in dia..my old button floats around inside of it. would you know by any chance how much to machine the back of the cam sprocket???..I also see that the shims are not as wide as the back surface of the sprocket...shouldn't they cover the whole width of that sprocket surface???


thanks

Brent rndsout@comcast.net
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Old Aug 8, 2004 | 04:26 AM
  #22  
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From: Houston, Texas
Car: 88' IROCZ
Engine: 388 TPI Motown 350 Race block
Transmission: 700R4
Axle/Gears: 2.77
If the thrush bearing & races were the same diameter as the sprocket they would interfere with the chain. You may get lucky and not need machining, but you really need the specs to find out.

Once you get the thrust bearing (block protector) installed and measure the end play put the shims (if any are required) in between the cam and button.

Try Summit CCA-202 for the cam button. I assume you bought the Block Protector kit from Summit, call them they'll help you with specs ( may even fax them to you.) Cam buttons also come in needle bearing types like the block protector.
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Old Aug 8, 2004 | 10:57 AM
  #23  
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From: NH
Car: 88 I-ROC
Engine: 355 TPI
Transmission: BW T5
I'll check out that button you mentioned from summit.My fear is that these shims have no "seat" to stay on...they will just fall down on to the cam when installed.or do they stay put when sprocket is tightened up,for there is nothing "holding" these shims on the sprocket or the block..know what I mean???
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Old Aug 9, 2004 | 01:04 AM
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From: Houston, Texas
Car: 88' IROCZ
Engine: 388 TPI Motown 350 Race block
Transmission: 700R4
Axle/Gears: 2.77
Originally posted by 88355
...My fear is that these shims have no "seat" to stay on...they will just fall down on to the cam when installed.or do they stay put when sprocket is tightened up,for there is nothing "holding" these shims on the sprocket or the block..know what I mean???
If you're refering to the end play shims, the sprocket must be installed first, the shims should be circular and of the same outer diameter as the cam side of the button (basically the same size as the center hole of the sprocket.) Besides putting the shim between the cam face and the sprocket would move the sprocket away from the block and then it would be out of alignment with the gear on the crankshaft. No part of the shim should rest between the sprocket and the cam, only between the part of the cam face that can be seen through the sprocket center hole and the cam button.

If you're refering to the block protector then when the sprocket is machined, it should "not" be machined flat, but with a step for the 2 rings and thrust bearing to ride on. This step should be the same diameter as the cam face, which should be the same as the inner diameter of the rings and thrust bearing. Besides if the sprocket were machined flat this would move the sprocket closer to the block and then it would be out of alignment with the gear on the crankshaft. That's why I repeat, you must have the specs.

Any machining done should not cause time gear misalignment.
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