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'90 Cadillac DeVille 4.5
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Discussion Starter #1
Hi,

I got a pretty good deal on a 1990 DeVille, 4.5L engine, 126k original miles at auction a couple of weeks ago. I had to do some minor repairs, brake lines, pads, new battery etc - still needs a bit of exhaust work but 90% of the time it runs really well. Recently however I'm running into an issue that I just can't figure out. It may be general automotive (I'm handy but not more than a backyard mech) or it may be indicative of the DeVille.

In a nutshell, when it gets hot outside (above 85 degrees F) and I drive the car more than a few miles, (5-10) after shutting it down I can't get it to start again. It cranks over just fine, but won't start. Normally I turn the key and it fires right up with a touch of the gas. If I leave it sit for a few hours (the hotter out the longer this seems to take) it starts right up. Is this vapor lock? I've got the Haynes manual for it but the troubleshooting section doesn't seem to cover this.

I have some thoughts of my own and I'm looking for a little peer review. Since the exhaust needs a bit of work I'm wondering if the heat from where ever it's broken could be heating a fuel line, causing vapor lock. I've tried finding the spot but so far I've come up a bit short - I can tell it's near the front, but not right at the engine. That would fall under general auto, not DeVille. Or, it could be something computer related. I'm hesitant to take it in to a shop as I bought the car for the sole reason that it was cheap and I was looking to spend as little as possible. So in the interests of keeping costs down I've come here first. Has anyone heard anything similar to this issue that might make it a DeVille related problem?
 

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Sedan de Ville, CTS
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4,764 Posts
That is why they still make wooden clothes pins. Try a couple on fuel line. Then have someone put scope on car. Crankshaft position sensor????
 

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White Diamond '03 DHS (with DTS floor shift)
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Does it have fuel pressure? Does it have spark? Did you pull the codes?
 

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'87 SDV
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1,296 Posts
Yes, check for trouble codes first. Read the sticky post at the top of this section for instructions.

Vapor lock can occur, but usually as a result of winter grade fuel or high alchohol content fuel. Next time it acts up, pull the top of the air cleaner off and observe the injectors as the engine cranks. There should be a light spray of fuel visible on the throttle plates. If not, the next step is testing fuel pressure.

You also might want to replace the fuel filter under the car. It's in front of the rear wheel on the driver's side.
 

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'90 Cadillac DeVille 4.5
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Discussion Starter #5
Okay, first - Thanks for the response. I was happy to see such quick replies. :)

One note: the sticky I looked up on these forums took a bit to find but I eventually found it under the Technical/Electrical threads. Someone might want to reorg the stickys - either that or I'm a complete idiot, parts missing.

The codes I got were

E12
E48
E49
E52

I think E48 is due to the exhaust issues, there's a hole in the system I still need to get fixed (catalytic converter and muffler appear in good shape), but hey - for the $225 I spent at auctiion and the $300 I've put into it since I can't complain too much (or shouldn't). I'll post a few pictures here once I figure how to. I think people would be amazed at what goes to charity auctions.

And thanks again for the help all. Is there a thread someone can link to that shows the codes?
 

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'87 SDV
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1,296 Posts
Sorry, I'm a little thick sometimes. I said at the top of this section thinking I was in the 4.x engine area. Here's the link to the sticky on codes:

http://www.cadillacforums.com/forums/ht4100-4-1-4-5-4/21558-obd-i-codes-4-x-engines.html

E12=no distributor signal

E48=EGR problem (most likely carbon plugged passages in the tubes at the bottom of the throttle body - very common and lots of posts here on what to do.

E49=A.I.R. system problem

E52=PCM reset (usually a result of disconnecting the battery)

Clear the codes to see which ones return. Enter diagnostics, wait for code cycle to run and .7.0 appears. Press OFF and HI simultaneously until E.0.0 appears to clear ECM codes, OFF and LO until F.0.0 appears to clear BCM codes.

It helps to have a factory service manual to decipher the codes. There are diagnostic trees for every code. You can usually find them on eBay for around $30 to $70. If you're handy, an FSM can save you a ton of headaches and money.
 

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'90 Cadillac DeVille 4.5
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Discussion Starter #7
Hey ND, Thanks for the tips. What is A.I.R.? Air conditioning unit? I'll get a FSM but can't afford one just now - got a little one to feed atm so any help you can give would be much appreciated.

I neglected one code when I typed in the previous post - I had E53 as well.

I cleared the codes, opened up the throttle body this weekend and sure enough the forward tube was clogged - nearly completely. I cleaned that out and it ran fine after - for a while.

The only code that's come back is E12 - which I know about. But here's the kicker, the car ran fine when I had the gas tank about half full. I ran it that way all weekend, drove some 60 miles on it (on some really warm days) - stopped, started, no problems.

When I stopped for gas about 5 mins from home on Sunday evning and filled it - still no problem. When I went to the garage about an hour later I moved it once about 10 feet to wash it, afterwards I had the same problem as before. It started, I put it in gear, it died and wouldn't start. I had too push it back into the parking stall. Is this a pressue issue with the gas tank?

What sort of fuel issues are pressure related? I'm thinking about going back to basics here and getting a can of starter fluid for the throttle body to see if it's a fuel/air issue, checking spark, taking the whole throttle assembly off and cleaning it up with sea-foam, cleaning the injectors etc. A bit more involved than before but I never thought any of those could cause some sort of fuel pressure problem.

P.S. - thanks again for the tips from before
 

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Cadillac Deville 1990
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266 Posts
Hey PapaShawn try a can of 44K from B&G. This stuff a way more powerful then any product off the shelf and it may clean your injectors enough to fix your problem. My 90 Deville was behaving in a simular way when it belong to my dad but he had a backyard mechanic do something or another and it seemed to have fixed the issue. Now what happens is that if I disconnect the battery it will not start unless I use starter fluid. The fix that guy did to my knowledge was a bypass on an electrical line but the funny thing was it would only die every so often and sometimes as it was running.
 

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'87 SDV
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1,296 Posts
I'm beginning to think your problem is spark - not fuel related. The returning E12 indicates a bad pickup coil or distributor circuit issue. The 1990-93 models are known for having brittle wires at the weatherpack connector at the distributor. Check that first. If the wires leading in are good, you most likely need a new pickup coil.

A.I.R. is the Air Injection Reaction system, which injects o2 to keep fuel burning after it leaves the combustion chamber. This reduces emissions, and preheats the cat during warmup. The system is pretty simple; a belt driven pump that forces oxygen to a diverter valve, and lots of tubing. The ECM tells the valve to send the o2 to the exhaust manifold, air cleaner, catalytic converter, or the atmosphere depending on conditions. Some trouble codes will deactivate the AIR system until the problem is corrected, but I don't think E12 is one of them.
 

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'90 Cadillac DeVille 4.5
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Discussion Starter #10
Thanks again all for the tips and advice, ND I think you're partially correct about spark but I'll lay out what I've got so far. At this point the car won't even start and I think I may have reached the point where I'll need to take it in to a shop.

The problem with the E12 code is, I think, a weak spark, but spark there is. I got under the hood again tonight and I took the distributor assembly apart, cleaned connections, etc. then took a plug out and tested it, it's definitely getting spark, allbeit what appears to inexperienced eyes, weak.

The more I dig around under there the more convinced I am that it's a fuel issue. The spark plugs themselves were completely dry. I checked the fuel rail and it's definitely got fuel in it, and under pressure so I'm thinking there is some issue with the injectors rather than the throttle body - I even tried some starting fluid and carb cleaner and had no visible effect. I've been reading through my trusty Haynes and all it talks about is taking everything apart and testing each individually with a special tool- which I'm not sure I can do. #1 I don't have the test tools and #2 I'm not really sure what I'm looking for.

So my sweet deal has turned a bit sour...sigh - back to the drawing board.
 

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'87 SDV
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If you put starting fluid into the throttle body and got no reaction, the problem is definitely spark. I'm sure you know, but be very cautious with that stuff. I know a guy who has half a face with permanant sunburn thanks to ether based starting fluid.

Since you have an E12 and no fuel related codes, the problem is either a short in the weatherpack connector, a bad pickup coil, or malfunctioning HEI module. If you can put your hands on a basic voltmeter, someone here with a 1990 FSM can walk you through the diagnosis tree (mine is an '87).
 

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90 Deville
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PapaShawn, Check your private messages, I might have something that will help. My alldata for 1990 might be of assistance...
 

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Cadillac Deville 1990
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266 Posts
PapaShawn,
Why not start from the basics and if you have some mechanic know how you can do this. If you think this is a fuel problem start with the filters, first replace the in-line filter and see if that fixes the issue, then if that does not work replace the in-tank filter and make sure you have your injectors cleaned before starting. I don't think it has anything to do with your fuel line heating up but start ruling things out and the filters are the cheapest start.

The in-line filter is $5 to $8 and two wrenches to remove. The in-tank is probable under $10 and only two straps and fuel lines to remove.

Remember a cars needs food and air so if you have a good air filter then it could only be food blockage or lets hope it is.
 

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Cadillac Deville 1990
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A.I.R. is the Air Injection Reaction system, which injects o2 to keep fuel burning after it leaves the combustion chamber. This reduces emissions, and preheats the cat during warmup. The system is pretty simple; a belt driven pump that forces oxygen to a diverter valve, and lots of tubing. The ECM tells the valve to send the o2 to the exhaust manifold, air cleaner, catalytic converter, or the atmosphere depending on conditions. Some trouble codes will deactivate the AIR system until the problem is corrected, but I don't think E12 is one of them.
So to fix this A.I.R problem do you need to replace the Oxygen sensors or what?:thepan:
 

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'90 Cadillac DeVille 4.5
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Discussion Starter #15
Okay - the dumbest thing just happened. I put the charger on it today - was getting it ready to send to the shop - when I decided to give it one more try. It started, ran, I drove it around the block parked again, it died, started, ran a bit more then died one last time and it's as before.... so it would appear ND is right - electrical.

Also, E12 code came back and a new one this time E98. Comments? (other than sell it :) )
 

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'87 SDV
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E98 can set if you shift into gear after revving the engine. Wouldn't worry too much about that yet.

Addressing the E12 isn't too tough. Borrow or buy a voltmeter and you can trace it (you will need to find someone here with a '90 FSM to help you walk through it). The parts are readily available and pretty easy to replace.

If you don't feel comfortable working on it, it may be cheaper to take it to a dealer. Ask for the tech who's worked there the longest. A shadetree shop may take 3 hours tracking it down, while an experienced Cadillac tech will diagnose it in 15 minutes.
 

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'90 Cadillac DeVille 4.5
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Discussion Starter #17
rstewart65 Thanks for the PM, I'd respond but the forum wizards say I need to have 20 posts before I can send a PM back to you. I'm going to spend the weekend working the issue. I found an O'Reilly warehouse about 10 miles from home and found the pick up coil and hall effect switch for about 20% less than any other place in town, plus they have it in stock - no one else does. If that fails to produce results I'll work the issue from the fuel tank forward, filters etc. I'll post results here in a few days. And thanks to everyone for their comments - you've all given me some good info and I'm happy to have found this forum.
 

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'90 Cadillac DeVille 4.5
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Discussion Starter #18
Hi everyone,

Update here

After a lot of trouble I got it running. Replaced the Pick Up Coil, Hall Effect Switch, screwed up the placement of the distributor so a friend and I spent Sunday fiddling with the placement of it in order to set the timing close enough to get the durned thing to start, which it eventually did.

I have codes E30 - idle and E98 - also idle/timing/gear shift related. (if these are inaccurate pls let me know)

The idle is all messed up and I think I do need to have the timing adjusted better than I can. I had to place the distributor in a position that looks nothing like what I started out with but in the original position it wouldn't start - just backfired, which told me it was firing on the exhaust stroke.

All in all it will run, but it does stall and has trouble starting. I've charged the battery again (nearly dead from Sunday) and I'm going to get back under the hood and see if all the spark plugs and wires are working -I'm confident placement is accurate.
 

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'90 Cadillac DeVille 4.5
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Discussion Starter #20
I actually bought a timing light and did it myself, but when reassembled the distributor only works in a position that isnt where it was when I started.

Also got code E30 - any help there anyone?


Right now it runs rough, but it runs. It dies when I'm at a light and it's a hard start, and it's louder than anything (was backfiring but we mostly fixed that)

Muffler shop is next on list after getting the timing readjusted.
 
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