I have installed my Injection Technology 4.9 harness in my 88 Coupe. I feels like it is taking off in 'Limp Mode' as it doesn't have the hard launch from a stop that it had before. I was gonna use my scanner to see if it would tell me the gear the transmission was in. It is not communicating with the ECM. Will Limp Mode disable the ECM from exchanging data with my AutoXray 5000. This all worked correctly before the harness was switched out.

I used a meter to verify the wiring for the ALDL, and they are correct

[This message has been edited by josef644 (edited 12-18-2010).]

Whats the differences in the two harnesses..??
My 4.9 isnt in 'limp' I dont think, but I think my lack of pop is in my tranny (4t60e). I think its in my modulator... not sure.
What tranny are you running..?? (i forgot)
SmoothGT

------------------
aka. SmoothGT
NotAFieroAnyLonger
CURRENT BUILD:
" SmoothGT-'w8nc' "
RIP. "Little Feather"

quote Originally posted by josef644: I have installed my Injection Technology 4.9 harness in my 88 Coupe. I feels like it is taking off in 'Limp Mode' as it doesn't have the hard launch from a stop that it had before. I was gonna use my scanner to see if it would tell me the gear the transmission was in. It is not communicating with the ECM. Will Limp Mode disable the ECM from exchanging data with my AutoXray 5000. This all worked correctly before the harness was switched out. I used a meter to verify the wiring for the ALDL, and they are correct

Joe, don't you need reprogramming from me to finalize your swap? manual or automatic tranny? if the car ran fine before, and now all of a sudden it runs weak using the injection technologies harness, i would say the harness is the issue. injection technologies quite often makes mistake in their 4.9L harnesses, the most common being the lack of 12v+ to the hot at all times pins on the ecm, as well as 12v+ to the power steering input... if you cant scan it, then something is amiss for sure.. i would look to the harness first, since that is what you changed, then i would look to the computer second.

Check the VSS wiring. There was an issue with their harnesses at one point. If that signal doesn't get to the PCM you will lose ~100-125 ft/lbs of torque at low RPM's. Also double check that the power steering input has +12v run to it. Its these little things they usually miss.

Unfortunately there is no code or anything that tells you that its in "limp mode". Its basically just a feel thing. If it doesn't feel right its likely one of these two issues.

Hope this is some help Joe.

[This message has been edited by Fieroseverywhere (edited 12-18-2010).]

quote Originally posted by stickpony: doubtful... even with the 4t60e, the 4.9L should snap your neck off the line

No, I wasnt saying the tranny IS the problem. I was just suggesting that I feel MINE might be the modulator. I know I have redone/added the vacuum line to it. When I got it it didnt even have a vacuum line to the tranny at all.
I havent had it back on the street to check it in awhile, because of the choptop, etc., I am in the middle of.
I was just trying to throw out a suggestion ......

Just got back to my PC. I am running the 4T60E.

My problem was where the wiring was around the ECM. When touched it would die. I would have to find the sweet spot again for the engine to run. I went ahead and purchased a ready made harness as I wanted to drive and not just keep troubleshooting.

I have already been 'Burned ' a bit by this harness. They made some changes , and left some of my correct connectors off the harness and replaced them with their own ones that did not fit my swap, such as Oil pressure sensor connector, and the coolant temperature connector.

Thanks for the tips on the harness. I will check the ECM connectors for VSS and PS tomorrorw with my meter tomorrow.

-Joe

Hey Joe,

I can't help much on the electrical side. Just wondering if you can manually put the car in first and see if it "launch's". Would any of the issues listed above cause the tranny to not auto shift to low? If so, would they not allow the tranny to go to low manually. Just thinking out loud.

Pat

quote Originally posted by josef644: Just got back to my PC. I am running the 4T60E. My problem was where the wiring was around the ECM. When touched it would die. I would have to find the sweet spot again for the engine to run. I went ahead and purchased a ready made harness as I wanted to drive and not just keep troubleshooting. I have already been 'Burned ' a bit by this harness. They made some changes , and left some of my correct connectors off the harness and replaced them with their own ones that did not fit my swap, such as Oil pressure sensor connector, and the coolant temperature connector. Thanks for the tips on the harness. I will check the ECM connectors for VSS and PS tomorrorw with my meter tomorrow. -Joe

i would replace your computer with another one too just to see if it changes anything...i had the same problem you had originally with your old harness on an olds ciera, and it turned out to be a cold solder joint on the pcb board in the ecm making a bad connection.

since you have the injection technologies harness, i am assuming you are running a 91-93 deville setup? what year is your tranny from? whats the part number on your computer? does it seem like you have only 2nd and 3rd gear(limp mode)?

quote Originally posted by katatak: Hey Joe, I can't help much on the electrical side. Just wondering if you can manually put the car in first and see if it "launch's". Would any of the issues listed above cause the tranny to not auto shift to low? If so, would they not allow the tranny to go to low manually. Just thinking out loud. Pat

PAT...
This is kinda what mine was doing... When I take off in DRIVE, it had umm... maybe 3.4 power. If I shift down into FIRST manually, then second, etc. its like having two 3.4s behind me...


Sorry, not trying to take over the thread, but maybe we can get 2 more 'beast' here in Texas tearing up the roadways...

quote Originally posted by katatak: Hey Joe, I can't help much on the electrical side. Just wondering if you can manually put the car in first and see if it "launch's". Would any of the issues listed above cause the tranny to not auto shift to low? If so, would they not allow the tranny to go to low manually. Just thinking out loud. Pat

As Fieroseverwhere said, you loose about 1/3 of your available torque in 'Limp'. I made danged sure I had it in drive where it has always worked before. This was the first thing I checked on Friday while test driving.

quote Originally posted by SMTHGT: PAT... This is kinda what mine was doing... When I take off in DRIVE, it had umm... maybe 3.4 power. If I shift down into FIRST manually, then second, etc. its like having two 3.4s behind me... Sorry, not trying to take over the thread, but maybe we can get 2 more 'beast' here in Texas tearing up the roadways...

SMITHGT this is a discussion on a problem I am having with my swap. Feel free to offer up any information you feel is relevant. I haven't modified my shifter to go into 1st position. I just have Overdrive, Third, Second gears

Umm, I had already said I wasnt taking over YOUR thread...
I was just saying what mine was doing, and that it might be the modulator...
Sorry again, I will leave it alone. Hope you find the problem.

quote Originally posted by SMTHGT: Umm, I had already said I wasnt taking over YOUR thread... I was just saying what mine was doing, and that it might be the modulator... Sorry again, I will leave it alone. Hope you find the problem.

SMITHGT,

I guess I typed incorrect. I meant for you to post anything you thought would be my, or your problem with our 4.9 swap.

Please, feel free to post anything you want to.

I also PMed you an apology

-Joe

[This message has been edited by josef644 (edited 12-19-2010).]

Hey Joe,

What year Caddy ECM are you looking for?

Can you disconnect the shifter cable and put it in low by hand? I guess I'm still unclear as to if the ECM can prevent the trans from going into low/1at gear.

Again, just thinking out loud.

Pat

1991-92- 93.

I havent tried to get it into 1st by removing the shift cable. Might try that tomorrow after I get all the connectors plugged back in.

[This message has been edited by josef644 (edited 12-19-2010).]

quote Originally posted by josef644: SMITHGT, I guess I typed incorrect. I meant for you to post anything you thought would be my, or your problem with our 4.9 swap. Please, feel free to post anything you want to. I also PMed you an apology -Joe

Not a problem, no apology needed.

quote Originally posted by josef644: 1991-92- 93. I havent tried to get it into 1st by removing the shift cable. Might try that tomorrow after I get all the connectors plugged back in.

joe, need these questions answered to help you further:
what is the part number on your computer? what year deville is the transmission from? what are your rpms when you are travelling at 70 mph? did you test continuity from the end of every sensor connector to the ecm connectors? if its a 91-93 deville setup, then you should have a 16132240 computer, and the chip should be prorgammed as a 91-93 deville.

if you are missing just first gear, its possible you have either a bad ECM, or a bad ground. look to the gear selector switch on the back side of the transmission. there will be two connectors, one will be a single row of pins, ALL of those wires should run to the ECM, and on the other connector, it will be a two row, 7 or 8 pin connector, and only one of those should be used, pin B, which should have continuity straight to ground.

you have to remember, that this is an electronically controlled transmission. it will not shift into first, even if you do it manually, unless the electronics are working properly.

feel free to call my cell if you need to pick my brain when you are working on it.

561-201-6191

Aaron

[This message has been edited by stickpony (edited 12-19-2010).]

quote Originally posted by stickpony: joe, need these questions answered to help you further: what is the part number on your computer? what year deville is the transmission from? what are your rpms when you are travelling at 70 mph? did you test continuity from the end of every sensor connector to the ecm connectors? if its a 91-93 deville setup, then you should have a 16132240 computer, and the chip should be prorgammed as a 91-93 deville. if you are missing just first gear, its possible you have either a bad ECM, or a bad ground. look to the gear selector switch on the back side of the transmission. there will be two connectors, one will be a single row of pins, ALL of those wires should run to the ECM, and on the other connector, it will be a two row, 7 or 8 pin connector, and only one of those should be used, pin B, which should have continuity straight to ground. you have to remember, that this is an electronically controlled transmission. it will not shift into first, even if you do it manually, unless the electronics are working properly. feel free to call my cell if you need to pick my brain when you are working on it. 561-201-6191 Aaron

I have a 16132240 ECM , out of a 91 Deville. My engine and transmission are out of a 93 Deville.

Never had it up to 70 MPH for a RPM check.

I verified all ECM connectors and the sensor connectors.this morning. The Ignition,12V+ and all grounds last night

Not so sure that I am missing 1st as I can not use my code scanner to confirm the gears. My scanner and the ECM are not communicating. If it is in 'Limp' it will seem like it is not in 1st.

I went out to look at the 7 pin double row connector. B on the C500 part is grounded, verified. The other wires there are for the back up lights and the start signal.

[This message has been edited by josef644 (edited 12-19-2010).]

Sorry to hear about your problems. It might sound like a pain but if you have someone to help it is a real snap to check the entire harness end to end and pin for pin. I had to do this when mine was acting weird. And then you will no for sure what it is or isn't. As far as ecm's go, go to a pick an pull it will only run you 10-30$ and it takes less then 5 minutes to remove.

quote Originally posted by Dizzixx: Sorry to hear about your problems. It might sound like a pain but if you have someone to help it is a real snap to check the entire harness end to end and pin for pin. I had to do this when mine was acting weird. And then you will no for sure what it is or isn't. As far as ecm's go, go to a pick an pull it will only run you 10-30$ and it takes less then 5 minutes to remove.

I verified all of the harness connections yesterday. I scored two ECM's today. One was a Genuine AC Delco Remanufactured unit. I am gonna try it first. $10.00 each. Got to keep my core too.
-Joe

I believe the tranny wiring changed some time after '91.
The changes have been documented here, fairly recently, even. I don't remember where, however.
Perhaps this will jog someone's memory.

Do you still have your old harness? You might try comparing the tranny wiring, comparing between the two.

quote Originally posted by Raydar: I believe the tranny wiring changed some time after '91. The changes have been documented here, fairly recently, even. I don't remember where, however. Perhaps this will jog someone's memory. Do you still have your old harness? You might try comparing the tranny wiring, comparing between the two.

I don't have my harness, but I used the schematics I used to build my harness to verify the Injection Technology harness. The only thing I could not locate was the Park- Neutral -Back Up light switch connector.

I will install the ECM I got today and see what gives.
-Joe

You mentioned that you checked the ECM and sensors in an earlier post. And in response to my question stated that you checked the entire harness. I assume that means you checked the C203 and all other fiero side connections as well?

If thats the case hopefully its a faulty ECM. Best of luck.

quote Originally posted by Dizzixx: You mentioned that you checked the ECM and sensors in an earlier post. And in response to my question stated that you checked the entire harness. I assume that means you checked the C203 and all other fiero side connections as well? The C500 was not checked, but I will do it before I proceed with the replacement ECM. If thats the case hopefully its a faulty ECM. Best of luck.

I have checked all ECM harness connections now. I could find only the one pin connector not seated in it's socket. C 203 was checked wire by wire Sunday and appears to be good to go.

Wasn't it your swap that the scanner would not work ,until you installed a different ECM?

-Joe

Diz, your thread:
https://www.fiero.nl/forum/Forum2/HTML/105001.html

[This message has been edited by josef644 (edited 12-20-2010).]

quote Originally posted by josef644: I have a 16132240 ECM , out of a 91 Deville. My engine and transmission are out of a 93 Deville. Never had it up to 70 MPH for a RPM check. I verified all ECM connectors and the sensor connectors.this morning. The Ignition,12V+ and all grounds last night Not so sure that I am missing 1st as I can not use my code scanner to confirm the gears. My scanner and the ECM are not communicating. If it is in 'Limp' it will seem like it is not in 1st. I went out to look at the 7 pin double row connector. B on the C500 part is grounded, verified. The other wires there are for the back up lights and the start signal.

limp mode on the 4.9L ecm has nothing different in the fuel delivery per say, it is distnguishable because the car actually starts out in 2nd gear.

now, are you sure that the tranny and engine aren't a '94?? 94 tranny's have a different pin configuration on the front tranny connector. if you use a 91 computer with a 94 tranny, and you dont use a 94 harness, you will start out in 2nd gear as if you are in limp mode.... however, since you are getting no communication from the ecm, i would suspect either yrou scanner is bad, or yoru computer/chip are bad..

swap out the ecm for a known good working one, and use a known good working chip. if the problem persists, then you KNOW it is in the wiring or the tranny.

This one?


Lifted this from M_M's wiring thread. It is the Park Neutral switch wiring and the range connector wiring sockets I could not locate earlier.


I just went out and re checked the round transmission plug. It is wired correctly for a 91 Deville. Also re checked the range switch connector, also correctly wired

[This message has been edited by josef644 (edited 12-21-2010).]

Double check the wiring for the fuel pump feedback circuit. This can also cause a "limp" mode of sorts if not connected.

quote Originally posted by josef644: I have checked all ECM harness connections now. I could find only the one pin connector not seated in it's socket. C 203 was checked wire by wire Sunday and appears to be good to go. Wasn't it your swap that the scanner would not work ,until you installed a different ECM? -Joe Diz, your thread: https://www.fiero.nl/forum/Forum2/HTML/105001.html

If you read the second page you will see that I tried swapping out the prom and that was not the culprit. In the end I went through the entire harness end to end including junction where grounds and things were tied together and checked every wire. I found that I had some problems in the C203 (dont remember exactly what) I think one wire in the ALDL and maybe one other issue. I completely re did the entire harness with silver fiberglass sheathed (good to like 2000 deg F) wire. I actually found that I had problems on my diagrams, thats why a while ago I re upped a revised edition of those.

Of course mine is a manual so there were a great deal fewer things capable of causing the kind of problem you describe.

quote Originally posted by Fieroseverywhere: Double check the wiring for the fuel pump feedback circuit. This can also cause a "limp" mode of sorts if not connected.

I will check this one first after installing the harness.

I spent the whole day working on a needy family's house and repairing their kitchen stove. Tonight a family of 5 can cook a hot meal. I am glad I took time off of my life to help someone in need.

All I did with my car was install one of the two replacement ECM's I got yesterday. I will be back on my car tomorrow morning.
-Joe

[This message has been edited by josef644 (edited 12-21-2010).]

Joe good luck with that gremlin. Wish I could give you a hand. Soon you'll have this worked out and be driving it normally.

quote Originally posted by Carrluvr: Joe good luck with that gremlin. Wish I could give you a hand. Soon you'll have this worked out and be driving it normally.

Thats all I want for Christmas, is my car working correctly.
Joe

Made some progress this morning. Replaced the harness, and installed one of the new ECM's. It scanned. First one would not let the car start and run, but just a second or two. It wouldn't even work with my VATS bypass connected . I suspect it is a 94-95 Deville ECM. They use a different VATS than the 91-93's. The second one worked with or without the bypass connected. I drove it a few mile this morning, until it started drizzling rain.

It still does not have the raw power of a launch from a standing stop like it used to have. But now I can drive down the road and check for the gear engagement, rpm, temperature, etc This is a big step from a few days ago.

I will not be doing anymore work in this car untill around the New Year.

Merry Christmas, and Happy Holidays to all of you good folks here at PFF.

[This message has been edited by josef644 (edited 12-22-2010).]

Congrats and have a happy holidays.

quote Originally posted by Fieroseverywhere: Double check the wiring for the fuel pump feedback circuit. This can also cause a "limp" mode of sorts if not connected.

I have a ??? Where is this located..?? After reading what Stickpony said about it starting out in 2nd gear.... Mine is doing that, but I thought it was a tranny or modulator problem... What are othe signs of 'limp mode' for this engine..?? Mines a 93 by the way if that matters...

Thanks for any help.

quote Originally posted by SMTHGT: I have a ??? Where is this located..?? After reading what Stickpony said about it starting out in 2nd gear.... Mine is doing that, but I thought it was a tranny or modulator problem... What are othe signs of 'limp mode' for this engine..?? Mines a 93 by the way if that matters... Thanks for any help.

The wire that comes into the C203 socket L should split off and tell the ECM that the pump is running at socket E13 (green plug), and also to pin G on the ALDL.

Fieroseverywhere would be the guy to talk to about Limp mode symptoms.

Here is a thread started by Sanderson 12-27-08 about his "Limp mode"
https://www.fiero.nl/forum/A...100421-2-097258.html

[This message has been edited by josef644 (edited 12-22-2010).]

quote Originally posted by josef644: Fieroseverywhere would be the guy to talk to about Limp mode symptoms.

I know a bit, but only because I've faced most of the issues head on a some point.

-Power steering input - Accidentally wired to +12v that was not hot in run. Doh. No signal disables fuel trim.
-EGR solenoid - missed second half of power wire. Caused some odd issues but not necissarily "limp mode" as such. Lowered power above idle, bogging down.
-Fuel pump feedback - Burned up from being too close to exhaust manifold. I'm using the caddy fuel pump relay and needed to route my wires better.
-VSS - constant issues only recently fixed. Interferance with exhaust manifold before pig tailing the sensor. Caused melting connector and wires to ground out, 1 bad sensor, bad VSS diff gear inside 1st trans, 84-86 fieros sensor wires reversed from caddy's caused sudden loss of signal under heavy acceleration. Extreme proof this PCM needs a speed signal. Feels almost like bad clutch slip.
-Many issues with O2 sensors - lowered power output, killed mileage. Don't use bosch sensors!!! Don't buy AC Delco either. Delco contracted out to bosch to build their sensors. Use only if you can find an older one that is actually AC Delco. Wagner (part # 250-22001) and Denso (2342001) work well.
-Bad PROM - #51 PROM checksum error. Causes multiple issues including full limp mode with no idle control and much lower power output. This one required a new memcal and took 8 weeks for it to arrive. I drove the car anyway.

I sure learned a ton during this adventure. It seems the first thing the PCM does when it detects a problem is lower engine output. Not one of these issues gave the exact same symptoms and most didn't set a code (or set BCM codes not readable without BCM). They all give headaches though! Now 9700 miles on the swap and engine issues mostly worked out. Whew! The car and owner still have issues though...

[This message has been edited by Fieroseverywhere (edited 12-23-2010).]