HT4100 4.1, 4.5, 4.9 Discussion, Ok ive given up on this engine. in Cadillac Engine Technical Discussion; The Valve timing seems to be out somehow. The fuel pressure seemed like it could have been the issue but ...
The Valve timing seems to be out somehow. The fuel pressure seemed like it could have been the issue but upon further diagnosis I determined my gauge was faulty. I checked the FP with a known good gauge and it stays 42-45 at all times. It has progressed to backfiring through the exhaust leading me to believe I have a mechanical problem.
Onwards and upwards. This car is in too nice of shape to send to the wreckers just yet. Most of its life was spent transporting donor body parts (human) 3000 km away. Each trip was ended by servicing the car and changing the oil.
Ive tracked down a 80.000 mile engine out of a 94 eldorado for $650. My questions are will this engine be identical? What should I look for visualy when picking this engine up? (its out of the car already but has a 90 day guarantee).
As long as the Eldorado engine is a 4.9 liter, then it will work fine. But if your valve timing is off, could it just be a skipped tooth on the timing gear? A new timing set would be cheaper and easier than replacing the engine!
SLOW DOWN! back fire can be caused by a bad dizzy cap, ignition mod, bad dizzy gear, shorted plug wires, shorted ground wire, ECM. Dont be pulling motor until a pressure test is done. is it running with a occasional pop? will it run? give me the history up to its demise.
Ok, Heres the history. Last fall the car was working fine and I put the snow tires on it and got it ready for the winter. A week later it started missing and sputtering like it had water in the fuel. I put fuel dryer in the tank but it didn't do anything. I got a code for the MAP sensor so I replaced that and no change. I then followed advice from this list and replaced the pcm , no change. I replaced the cap rotor wires and ign mod, no change. I checked the timing a dozen times and its set properly. I replaced the entire distrubutor, No change. A year or so ago the bottom end was rebuilt due to what I thought was low oil pressure. Turned out to be an after market sensor. Ive checked the fuel pressure and its 42-45 and steady. Vacuum is low when it is running poorly and 22hg when its running good , Yes it will run good sometimes for 1 or 2 hrs and you will think its repaired and then its back to the sputtering and missing and now backfiring. My thoughts are that the ECM was trying to take care of the valve timing by retarding the ign timing till it got too far out and now it can't. There is a lot of miles on this engine and there are plenty of them on the used parts market with a lot less miles. As for cost of doing a timing chain and gears knowing the top end has run dry of oil a few times for about 10 seconds ( I heard the ticking of the rockers) I think that unless it is a bad ground which I am going to go check as soon as I finish with this than I will put my new parts on a wrecker engine and be done with this for a good long time.
I just returned from testing the engine ground with a set of booster cables from the - battery term to the engine and from the strut bolt to the engine. No change. I seriously doubt its a ground , I checked each wire from the engine to the ECM when I replaced the ECM. Ive replaced every component in the ignition system with top notch stuff ie wells cap , ac plugs , bosch wires. the only other thing I can think of is the reman distributor. Are they all compatable through the years say a 4.1 or 4.5 to a 4.9. There was a disclamer in the box with the reman dizzy that read like this I have installed D2142
Part # D2124 and new part# D2142
Due to an error in our 2001 catalogue, this distributor may be incorrect for your application
To ensure the correct part # is being installed, please refer to the following changes:
This info doesn't seem to have any bearing on my application just the 4.5 and the D2142 is listed as being the correct part for the 92 DeVille. I did notice a slight difference in the parts but dismissed it as an improvement. The trigger on the reman Distributor has just a tab and the factory part has more of a cup shaped device with a window cut out of it? I had to give the original as a core so casting #s mean nothing to me now.
I hate the thought of shelling out another $350 for a non returnable part that may or may not work. I can buy a known running engine and try the distributor from it and still end up with a whole lot of spare parts as well as a rebuildable core engine.
Automobile(s): 1995 FWB 100,*** miles CURRENT. 1991 Seville 175,000 SOLD
Re: Ok ive given up on this engine.
There is a ground by the starter. It may look good, but taking it apart, replaceing the 8mm stud, star washers, cleaning contacts would hurt nothing but in some cases made huge difference. Just a thought...
If it runs good for awhile then screws up then its an electrical problem. Its not mechanical the way you describe the symptoms. Slow down and think grounds , something is grounding out . something is taking away its spark.
I agree with you lenny. Today I did the TDC thing again and advanced the distributor one tooth and reset 10* and got no results. I then decided to replace the Ign module with one I bought before I replaced the distributor. Suprise suprise I got a code 23 (est signal fault) so that leads me to believe that I got a dud module . I then replaced the module with the one that came with the new dizzy and reset the timing and whatyaknow it runs ok, not great but ok. I took it for a 10min drive hammering the crap out of it and I got some new codes 62 and 65. These are cruise control system fault codes and im wondering if there is anything there that makes this puzzle come together yet?
I agree with you lenny. Today I did the TDC thing again and advanced the distributor one tooth and reset 10* and got no results. I then decided to replace the Ign module with one I bought before I replaced the distributor. Suprise suprise I got a code 23 (est signal fault) so that leads me to believe that I got a dud module . I then replaced the module with the one that came with the new dizzy and reset the timing and whatyaknow it runs ok, not great but ok. I took it for a 10min drive hammering the crap out of it and I got some new codes 62 and 65. These are cruise control system fault codes and im wondering if there is anything there that makes this puzzle come together yet? Oh and advancing the dizzy housing will alter the cam position sensor which might explain some of this?
recheck your firing order again, check your wires and make sure they didnt short out some where. Put the dizzy back in at TDC, use your thumb and pressure to find. If you get it running start pulling wires off the cap one at a time and listen to the engine, you will find the miss.
These days control module quality is suspect from many vendors. When the rebuilders buy them they get the cheapest ones, regardless of quality and reliability. Think about it, it's $30 at Autozone, so they buy it for $15 from somebody who gets it from China/Taiwan/Vietnam for $5 and it's made from who knows what... Even buying from NAPA doesn't protect you since everybody is price point driven. In almost every case you can expect a good quality part from Standard Motor Products, but you'll pay for it. Same seems to hold for caps, rotors, wires etc. Just a quality name doesn't gaurantee quality. Bosch filters and wires you buy in the USA are not German made, in many cases they are little more than re-boxed white-box parts.
Reman distributors are often little more than repainted used distributors. I toured one rebuilder (I was in the parts business for 20+ years) and all they do is dis-assemble a batch of distributors, bead blast and paint the housings, test the control modules and pickups, discard the ones that fail and re-assemble the unit. There is a huge chance that the "rebuilt" you get is nothing more than a cleaned up used part.
Check everything in the ignition system. Lenny's right, pull one wire at a time, move things around. Don't forget the spark plugs. They are getting like the modules. Think about it, you pay $2 for them and at least 2 or 3 guys before that made money on them, plus they are shipping them from overseas. I've seem more defective plugs in the last 5 years than I ever saw in the past. I speak from experience as I had a similar problem 2 years ago in another car and it ended up being a bad new nippondenso plug. Talk about pissed, a whole weekend of work, diagnostics and all it was was a bad gas seal in the plug...but then again plugs are the same price they were 10 years ago. We get what we pay for!
HUF and lenny_lincoln are right. The ground near the starter will cause erratic behavior. No offense, but you may have installed hundreds of dollars of problems in your car.....very hard to diagnose. I'll bet some experienced tech at you local Cadillac dealer would have fixed it for half of what you spent in parts.