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92 4.9 Timing Marks (and about to lose my religion over a dead miss.


CarolinaGreg

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Does anyone know what the gradients are on the timing marks on the water pump on a 92 SDV 4.9? And where is zero? I need to check my timing, seem to have a severe spark knock at WOT.

Worked on the 92 nearly all day today to try to find the dead miss that it has developed and have come up dry. No codes are coming up in the information center, my brother's Snap-on scanner would not come up with anything either. My brother (who is a full time mechanic of nearly 15 years) helped check the EGR valve, we checked ohms on all injectors, can't find any vacc. leaks, and even swapped out the coil in the distributor. The miss is sporadic, (probably 80% of the time) but is most definitely one or two cylinders dropping off, causing the entire car to shake when it does it under load. Fuel mileage is terrible. Have recently replaced spark plugs, wires, cap & rotor, fuel filter, PCV Valve..as we initially thought it was a bad plug wire. Going to rebuild the distributor next, as we think we have ruled out fuel delvery, as we think it is a firing problem at this point. I wish it would just leave me on the side of the road and I could actually fix it.

Anyone's two cents on this would be GREATLY appreciated..It's bad to want to drink this much on a Sunday after this day..

Thanks, Greg.

"Torque it down 'til it strips. Then back off half a turn."

www.picturetrail.com/carolinagreg

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There should be 6 teeth on the water pump cover. The tooth closest to the magnetic timing probe hole is the zero. The next is 4 deg, 8,12,16,20 deg. The recommended timing is set at 10. Check the timing when engine is hot.

The saddest thing in life is wasted talent

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See this thread for all you wanted to know about timing the 4.9, Scotty's post #15, 16, 43, 44 and 48 shows the set timing procedure and other distributor related information. You need to jump the ALDL connector to enter the timing mode, see post #15 if you need that info, Mike

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If by FPR you mean fuel pressure, yes, we did. Can't remember what the reading was, but was within spec according to the manual that came with the gauge. Seems like it was in the 30's but I really don't remember, as as soon as we realized we were within spec, we moved on...I went out when I got home and pulled the battery cables off, they were as clean as you could wish for, and seemed tight. I wish it was something as simple as that.

Ordered a module and pickup for the distributor today, will start throwing those parts at it tomorrow.

GRRRRRR

"Torque it down 'til it strips. Then back off half a turn."

www.picturetrail.com/carolinagreg

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FPR = Fuel Pressure Regulator. Pull the vacuum hose at idle and look for fuel at the nipple. If there is any, it needs to be replaced.

Fuel pressure should be about 45 psi if I remember correctly. Definitely higher than the 30's.

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FPR = Fuel Pressure Regulator. Pull the vacuum hose at idle and look for fuel at the nipple. If there is any, it needs to be replaced.

Fuel pressure should be about 45 psi if I remember correctly. Definitely higher than the 30's.

I'll check the regulator tomorrow. It was in the 40's..it was within whatever the manual said...I've never been able to remember figures. :)

"Torque it down 'til it strips. Then back off half a turn."

www.picturetrail.com/carolinagreg

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The EGR system should not be a factor at WOT but could you be getting spark knock on acceleration, not just WOT? If so, I would check the EGR delivery tubes visible by holding the butterfly valve open. They should not be caked up with carbon. If they are, rod them out with a piece of coarhanger wire.

Have you checked for trouble codes in the onboard diagnostics?

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Have not noticed a spark knock at normal acceleration. Module and pickup came in today, but won't have a chance to change tonight..Will report back tomorrow.

Update- I decided to go out and run codes on the DIC one more time and see if I got anything. Never had any success until now, and it flashed "E53"..from which I understand is distributor related. I think we may be on the right track. I let it idle while doing some other things in the garage, and it died..and took 4 tries to crank back..car has always fired off on the first try. Think I may be getting close. I wish it wouldn't have started back, then it would be an easy fix.

Thanks again for all the tips guys..This place is Grrrreat.

"Torque it down 'til it strips. Then back off half a turn."

www.picturetrail.com/carolinagreg

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The E53 code is the distributor signal code. My guess is the pickup coil on the distributor is bad or the associated wiring is damaged.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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:angry: OK Folks. I am just flaming ticked off. The 92 got so where it wouldn't start at all. Dead in the water. Tried it one more time this afternoon and was still just spinning.I finally got around to changing out the pickup coil on the distributor (the non-Hall effect) piece..and the car started up...AND STILL IS RUNNING LIKE CRAP! I ran the codes and am not getting the E53 code anymore, only E52, which I assumed was because I had unhooked the battery. Should I change the hall-effect piece? The only thing that is different, is the coil...I changed it with one I had on the shelf last week to see if that fixed the problem but it didn't. I am wondering if this spare coil of mine was possibly bad causing the no start condition and when I had the distributor out and jostled around, the coil started working...?

I've reached my wits end. Please don't make me feel insecure in my manhood by taking it to another mechanic for diagnostics. :(

"Torque it down 'til it strips. Then back off half a turn."

www.picturetrail.com/carolinagreg

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Greg,

My 92 4.9 had a problem similar to yours, it was the wire coming into the distributor below all the components shorting to the casting due to vibration wearing through the insulation.

Hope that will help you also?

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:angry: OK Folks. I am just flaming ticked off. The 92 got so where it wouldn't start at all. Dead in the water. Tried it one more time this afternoon and was still just spinning.I finally got around to changing out the pickup coil on the distributor (the non-Hall effect) piece..and the car started up...AND STILL IS RUNNING LIKE CRAP! I ran the codes and am not getting the E53 code anymore, only E52, which I assumed was because I had unhooked the battery. Should I change the hall-effect piece? The only thing that is different, is the coil...I changed it with one I had on the shelf last week to see if that fixed the problem but it didn't. I am wondering if this spare coil of mine was possibly bad causing the no start condition and when I had the distributor out and jostled around, the coil started working...?

I've reached my wits end. Please don't make me feel insecure in my manhood by taking it to another mechanic for diagnostics. :(

Like Popeye said, its something around the distributor. Get an ohm meter and start checking continuity. Be methodical. When you replaced the anode in the distributor (the carbon bit in the center of the distributor) did you include the rubber 'gasket' 'seal' that goes around it?

Check all wires as popeye states. Sounds like you are getting close

Pre-1995 - DTC codes OBD1  >>

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:angry: Well the goose chase continues. It wasn't the hall effect switch, module or coil. I traced every possible wire I could find going to the distributor and all were in good shape. It was still missing bad and we pulled plug wires off (after disconnecting the ISC to keep the idle consistent) and it isn't firing on cylinders 2 and 7. Took those plugs out and they were extremely fuel fouled. Cleaned them up in the bead blast cabinet and reinstalled and was running fine..drove it about 2 miles and was running like brand new. Got back home and the miss started again. Keep in mind, we have checked the injectors and all were within spec, but we decided to switch he injectors between #'s 5 & 7 to see if we could move the miss to #5. Didn't work. I looked at the print outs of the wiring schematic of the injectors that I found on this site, and the 2 and 7 do not share anything in common, both go to different fuse blocks. For giggles, we checked the compression on #7, and it was over 100 lbs. We have traced it down to these two cylindrers, but just don't know what could be causing the problem. I have ordered a GM service manual and should be here first of the week, hoping to maybe be able to trace some more with it. I am wondering if somehow the ECM is not sending the signal to the these injectors?? Still getting no codes on the DIC.

This is the darndest thing I have ever seen, and keep in mind my mechanic (my brother) has over 15 years mechanic time under his belt, and we do all our own work...and we are the people that get called when someone else can't figure something out. and we are just stumped.

If we can't figure it out with the service manual, I guess I am going to have to take it somewhere.. Or sell it one.

Thanks,

Greg

"Torque it down 'til it strips. Then back off half a turn."

www.picturetrail.com/carolinagreg

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Listening to the injectors with a stethoscope should tell you if they are operating.

Good tip. Will try that next. I think the problem lies in the power getting to the injector, just seems odd that 2 would go at the same time. And I have only ever seen one actual injector go bad, in my driving life. Who knows at this point.

"Torque it down 'til it strips. Then back off half a turn."

www.picturetrail.com/carolinagreg

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Have you tried a power balance test yet? The power balance test allows you to turn off each injector one by one, record the RPM drop. When you find an injector that has NO RPM drop you found your problem.

Do you have a PCM that you can swap in, we have seen PCMs in 92's create havoc. Try putting a jumper cable between the engine and the FRAME or negative battery connection and see if it improves, we have seen bad engine grounds in 92

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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You know, I have been sitting thinking about this..watching the Disney Channel with my daughter. You said that cylinders 2 and 7 have nothing in common, and that made me begin to think.

Well they may have something in common after all. The firing order on the 4.9 is 18436572. Notice how cylinders 7 and 2 are consequtive... Pull the distributor cap and look for cracks, between the towers, carbon tracking between the #2 and #7 towers they are side by side or look for bad contacts. Look closely.

Mike

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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I do appreciate all the advice and encouragement.Have a list of things to do from here. I have a GM manual on the way (ebay) and hope it will help. I attempted to search for the procedure on the power balance test for this year car but can't find it...Can anyone enlighten me?

Mike- We did actually change the dist cap from the onset of the problem..Initially thought it was a bad plug wire and did a full tune up.Glad to hear I am not the only one thinking about this tonight. Sitting here with the laptop while the wife watches Maury Povich..Ahh married life. The greatest.

"Torque it down 'til it strips. Then back off half a turn."

www.picturetrail.com/carolinagreg

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I do appreciate all the advice and encouragement.Have a list of things to do from here. I have a GM manual on the way (ebay) and hope it will help. I attempted to search for the procedure on the power balance test for this year car but can't find it...Can anyone enlighten me?

Mike- We did actually change the dist cap from the onset of the problem..Initially thought it was a bad plug wire and did a full tune up.Glad to hear I am not the only one thinking about this tonight. Sitting here with the laptop while the wife watches Maury Povich..Ahh married life. The greatest.

Don't assume that that cap is good, take a close look at it. that you identified #2 and #7 and that they are adjacent on the cap, makes me want to look... Maybe you were NOT getting a #2 and #7 miss before and that it was a DIFFERENT miss...

I will scan the Power Balance test out of my manual if I can't find it in a search

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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Service manual came today...looks brand new..No fingerprints at all. (ebay)..Maybe we will be getting somewhere now. Lots of good information.

Mike- Appreciate it, don't worry about scanning the power bal test..THANKS!

"Torque it down 'til it strips. Then back off half a turn."

www.picturetrail.com/carolinagreg

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Alrighty folks- Talked to a "friend of a friend" that worked for a GM dealer for nearly 30 years as a tech and recently retired and opened his own tire store. He reccommened replacing the ECM, as we have tested, replaced and thrown parts until our heartIs content. Now the question is...would there be any risk involved to other systems by purchasing a junkyard ECM? Pull-A-Part has them for around $30 (I think) and the location near me in Charlotte has five 92 devilles on the lot. Advance Auto Parts sells a remanfactured unit for about $88. I hate to buy the $88 one, since we are we still in the "throwing parts" stage.

Argggggg...I want to get this thing fixed so I can start playing with my new toy..My 85 Eldo.

"Torque it down 'til it strips. Then back off half a turn."

www.picturetrail.com/carolinagreg

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Could be a bad ECM, but they usually act up when engine is hot (I guess because ECM is very close to the heater core). Tapping on ECM when the car acts up is commonly used to localize the problem.

Folks who replaced their ECM will likely chime in to share their experience.

The saddest thing in life is wasted talent

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Look at my post #17 above, I recommended swapping in a new or used PCM and that we have seen bad PCM/ECMs on 92's

See these threads, they are related you will see that DIETER went crazy trying to find a problem:

Dieter PCM/ECM Problem Thread 1

Dieter PCM/ECM Problem Thread 2

See this thread

Astrak ECM Problem 1992 4.9

There are more but I searched for over an hour and couldn't find them..

Mike

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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