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Hey thanks Logan, now that is interesting

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apperiate all of you guys fisher? thanks for phone conversation small world westchester I'm sort of like you 51 years 22 years of truck driving and seeking a better way I've been told missed my calling for mechicanic DAD RIP 35 years at same shop first guy hire 1973 concord autobody concordville pa he could make a rock move. Bruce apperiate your site and memebers help Caddy TECH ? yes sir a&b jumper timing set @ 10 Fisher could explain better then I after our phone conversation. I'm going to pull rail my car runs fine went through everything myself I'm going to check for leak injector there are no codes coming up DIC display 46 intermitted as explain to fisher. More then likely injector issues which will cause back fire.I'm little nervous with power steering pump moving it for access gain for number 1 injector went to bone yard today crab 4 used injectors also order new orings also have spare fuel pressure regulator with key left on she drops pressure FSM manual says supposed to stay steady key keeping pressure where it's not. going to start on it tommorow. Fisher clean up post as spoke about lol

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Good Read Logan thanks, I learned my something new for the day. I was not aware of that at all.

Dave I was asking, did you jumper the ALDL before you started the car? If you did NOT jumper it BEFORE you started the car it will NOT be in set timing mode and the computer will still be controlling the timing. If you adjusted the timing while the computer was controlling the timing it will be wrong.

Edited by OldCadTech

THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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And.....if the 'backfire' is happening in park or neutral....it could be the ECM hitting the rev limiter.

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did my plugs i'm 6'3 remove strut bar helps i laid card board over engine and got after it most feel for plug number 8 was hardest for me i have big hands also change both 02 sensors that went smooth basically complete tuneup including fuel filter wires IAT sensor egr pcv air filter because she failed smog test first time around

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logan change neutral switch which cause some problem E091 which solve service soon 3 appeared on DIC Tech you can call anytime brother 219 314 1854 OH Logan swap out ecm did change my problem also checked all ground points known in car appreciate your help Logan

Edited by dbc2065
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That ECM might be an export?, Logan?

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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swap ecm out only to see if any change there wasn't fisher ecm swap with came from 92 eldorado with same prom ID number. Believe my problem is fuel related injector pump or pressure regulator.Yesterday done balance test FSM Page 6E-A-18 not sure is done right when it says disconnect isc jumper? are they referring to unplug harness at isc? One other question please fsm page 6e-a-20 fuel pressure injector flow test will tell me fuel pump or regular leak what use to block off return line it speaks of a tool block line off with? Do I block off at rail end or tank end were it meets topside off engine.

Edited by dbc2065
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David, I am NOT saying that the ECM is your problem, I am saying that the ECM you swapped in may have been from an export vehicle based on the way it is acting, flashing 46. Logan taught us all something new.

Please answer these questions:

1) when the backfire occurs is the car in DRIVE?, or PARK/NEUTRAL?

2) when you set the TIMING MODE (jumped pins a and b at ALDL) did you set it while the engine was running or key off?

Keep your answers short and to the point for clarity.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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To clarify.....the export settings are stored in the the IPC. Not the ECM. So a different ECM would have no effect on the 46 problem. The 46 problem is likely because the IPC has been programmed into export mode. (Why?....could be different IPC....maybe from Canada....could be someone in the past flubbed the settings in the IPC....perhaps by mistake.)

What is a export code 46? No one knows....we could not figure it out back in 2003. All the export cheat sheets were exported. The export codes are not mentioned in the North American service manual.

Many GM cars....for a long time.....will start shutting off the injectors above maybe 3000-3500 rpm in park or neutral. A type of rev limiter. This should not be mistaken as a 'backfire'.

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Yep, my mistake....I actually noted the IPC in a prior post, sorry. When i saw him mention he replaced the ECM it clicked in. My mistake

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Key was off for timing mode place jumper a/b then turn key on first confirmed timing mode display. Only swap ecm to see if any changes back fire was still present so original ecm back online. Fisher car only backfire at park under load as mentioned to you on phone this morning check fuel pressure again. Key on 40 PS then drop to 36 while key is on. Then when start running drops to 35 PSi Reguator vacuum line pulled 42 psi. Car is not holding pressure key on check. My computer crashed on my phone with this sorry for any confusion

Edited by dbc2065
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Ok, answer yes or no.

Your backfire ONLY happens in park?

Take the car out on the road, and floor it to 55. Tell me if it backfires.

As Logan noted, in park you might be hitting up against the rev limitor. Drive it and hit 3000 rpm + on the highway

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Rev limiter is controlled by ecm right awfully low about 3000 rpm. My problem is fuel related guys thanks going to check for injector leak. Key on fuel pressure test failure doesn't hold pressure.going to pull fuel rail inspect for leaks

Edited by dbc2065
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I think you are wasting your time. Ill let others chime in. If it is not backfiring IN GEAR, you dont have a problem.. As Logan said you are bumping up against the rev limiter in Park and N. Its there so you dont damage the engine.

I think you are wrong about the fuel pressure, my manual states fuel pressure should be steady 34 to 38 in all engine speed ranges.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Checking injector there's a leak somewhere I'm going by my manual fuel is not holding steady appreciate Logan and your help and time Caddy tech help going to pull rail

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Yeap.....chasing our tail.....

They will run like *smurf* above 3000+ rpm. You think there is a problem. No....it's the ECM turning off the injectors.

The 46 is not causing the problem.

I'm not too concerned about the fuel pressure dropping off. Most GM cars will do this in the real world. They rarely will hold pressure like the service manual demands..it's really only a problem if the car is hard starting or has long cranking times.

There certainly could be a miss. No P0300 codes available on a '92. Could be a poor flowing / gummed up / rusty injector from sitting.

There is a way to turn off each injector one-at-a-time via the IPC for balance testing.

post-2-0-26953800-1464478753_thumb.jpg

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Thank you Logan

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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If it makes you feel better by all means pull the fuel rail, at the very least you will replace the injector O-rings and determine if because the car sat so long an injector is acting up.

Right now, having eliminated the E046 code, backfire in neutral that is related to the rev limiter, the fuel pressure that appears normal once stabilized, the only other symptom you are experiencing is black exhaust. You never confirmed a fuel smell at the exhaust however. You might as well satisfy you curiosity and pull the rail.

If you dont have a leaky injector and NO CODES I am not sure what would cause the rich mixture you experience (the black exhaust) but unconfirmed fuel smell at exhaust. I will do some reading to see how we can confirm that your engine managment system is in closed loop, ie, the fuel mixture trim is controlled by O2 sensor data. Open Loop causes a rich mixture sort of like the old school choke did. But you would need a P code to stop you from going into closed loop and based on our discussions you are not getting any codes.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Don't want to argue with you guys yes Logan there is a test in FSM for injector have listened pages reading from according to Fan it does turn off with cooler button to compare rpm drop pages are listen page 4 of thread again appreciate you guys Fisher could you clear threads

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*

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Dave,

No one is arguing with you! Everyone is trying to help you.

Diagnosing a problem from a distance is extremely difficult to say the least. We all evaluate the symptoms based on your description and we give an educated guess as to what the problem MIGHT be or checks to perform to verify a defective part, this is based on our experiences and knowledge. The language barrier is a difficult hurdle to overcome but we try to work around it as best we can.

1) Logans description and analysis of the IPC being in export mode 46 is exactly as you described the display reacting - I, and if I may speak for the others, agree this describes your "problem". You should reset the IPC to factory domestic (US) settings and see if normal E codes display. Read Logans' link from 2003 for the reset procedure. Up to you though.

2) If you do not have a backfire in gear at any engine speed then the most logical explanation is the software built into the ECM to prevent unwanted and unnecessary high RPM in park or neutral. This is known as a "Rev Limiter". This protects the engine and the transmission. WE can not hear what you hear! To us it appears to be normal operation. You should connect it to an engine scope. You can see very easily if it is a miss or not. That is why I suggested putting it on a scope.

3) The service manual is a TOOL !! It is NOT ALWAYS RIGHT !! That is why GM has thousands of service manual updates and tech bulletins every year. If the vehicle is starting normally, idling normally, and performing under load normally with reasonably good fuel mileage it is NOT broke. The "real world" operation beats the service manual every time. A weak fuel pump will make the vehicle hard to start and it may die under load, such as a hard pull up a hill. fuel pressure while the engine is running is the most important reading anyway. The service manual's results are results under perfect conditions. We all know the real world isn't perfect.

4) It is probably a good idea to check the injector seals and replace them. Also the injector leak test that Mike (BBF) suggested is a good idea to do. Be very careful, one stray spark and the engine could catch on fire. The only way to accurately check a fuel injector is with an injector tester. That is listed in the service manual also. Do you NEED to do the injectors? Probably not if you sprayed brake clean around them and there was no change in RPM. If you are using used injectors from a "Junk" yard you could very well be replacing a BAD injector with another BAD injector. It is your choice... I wouldn't do it that way but it is great if it works :)

Sorry it took so long to get back to the thread, I've been working the day job and working on the '02 STS - fixin stuff somebody already tried to fix. Grrr :P

THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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