• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

Engine Trouble

98GTFan

98GTFan

New member
Ok so this all started a few days ago on my 98 GP GT. It had been running fine all day with no signs of trouble until I was about 300feet from home (lucky for me). It started to choke and sputter and run rough as hell for about 5 seconds then completely stopped running but i was able to coast into my driveway where it has sat ever since. I did all the obvious checks, O2 sensors, filters (air and gas) fuel pump, coolant, oil, spark plugs and fuses and they all checked out fine so i turned to my code scanner for help as i noticed the check engine light come on seconds before it died.
It scanned the p0301 error for cylinder one misfire so i thoroughly went back over my ignition coils, plugs and cables to make sure they weren't fouled in anyway and they cam up clean so I turned to google for help. After some searching i found a thread mentioning common causes of the p0301 error (its how i came to find this website actually) and it mentioned that the crankshaft sensor reads directly off cylinder one to determine the shaft position and occasionally a fouled crank sensor will throw the p0301 error.
After a lot of work getting the tire and crankshaft pulley off I replaced the camshaft and crankshaft sensors just for good measure and put everything back together. The engine then wouldn't start because it had become flooded due to the spark plugs not firing correctly and the starting attempts from earlier in the day so I aired out the engine and FINALLY it turned over.
However, it wasn't over yet as the exhaust was very smokey although the engine was running smoothly and holding a steady rpm. So i turned it off to check the plugs again and check compression to make sure my head-gasket hadn't started leaking. Compression checked out, fuel pressure checked out and the plugs showed no new signs of residue, however when i went to restart the car again to burn off what i was hoping to be just moisture and sediment from sitting for 3 days, it wont crank.
I just replaced the starter 15 minutes ago assuming i had burned it out by cranking the engine to try to start it the last few days and to vent out the flooded gasoline, it still wont turn over. I can hear the starter engage clearly, then it just cant turn the engine over. I used a DMM on the battery and its reading 12V+ and I tried jumping it with my other car and that wont work either, still just the clang and no crank. I can turn the engine using the crankshaft pulley with a wrench so it didn't throw a rod or seize, nothing is blocking the pistons.
Any idea why it won't turn over?
 


hm, well it is unclear whether or not the original issue is fixed or not.

how many miles are on your car, have you done LIM gaskets, have you checked all the vacuum lines?
 
hmm. well you say you've checked coolant/oil/compression but from the sound of it locking up like so it reminds me of having coolant on the top of the cylinders. if this is possible, then i'd say UIM because on the GTs they fail around the EGR area because it's so hot and they're made of plastic and they will leak right on top of the cylinders like mine did when i had a GT.

there's something preventing it from turning over so we gotta figure that out
 
the thing is that there isn't anything preventing the engine from turning, i can crank the engine by turning the crank pulley by hand.
 
When you say at the end of your first post "Still just the clang and no crank":
Do you mean you hear a solenoid working making the "clang" noise without any actual "turning over"? Or is the starter just struggling like hell and just stopping abruptly?

My roommate's Lincoln Town Car (not sure of the year, mid 90's though) had a problem where he'd turn the key and all he could get was the solenoid to click on. Nothing would make the car turn over (at least from the key). Turns out it was an electrical connection that detached! He plugged it back in and it started right up.

Although your car undoubtedly benefited from all the love you just showed it by replacing sensors and whatnot, I'd follow up by re-checking everything you disconnected. Good luck.
 


I went back and double and tripple checked all the wire connections to make sure they were all connected and they were, sadly, i was hoping a simple mental oversight was the issue. I also took the plastic cover back off the starter so i could see exactly what it was doing when i tried to turn it over.
Having a friend turn the key I could see the starter gear fling into place up against my flywheel (thats the clang noise) then it just cant seem to turn it from there. Im assuming either my battery is totally shot, or my engine is hydrolocked. Is there an easy way fo me to check for hydrolocking without taking everything apart to get to my head-gasket or intake gasket?
In the meantime im going to have a friend bring over his heavy duty jumper kit and see if i cant get the old girl to kick over.
Keep in mind that after i replaced all the ignition coils and sensors it did start and run smoothly twice, i just didnt keep it running due to the smokey exhaust.
 
remove all the spark plugs and see if it cranks, and if so keep an eye out for coolant coming out of the spark plug holes.

you could just have a dead battery.
 


Sorry for the delayed response but I finally got some more time to test and examine the engine and im near 99% positive I have a blown headgasket. After sitting for a few days while I was busy the engine has become hydrolocked and I had to remove the spark plugs to drain the cylinders, however; only the number 2 cylinder was filled. The others seemed relatively fine but I couldn't be 100% sure because only the number 2 physically glugged out coolant once i got the spark plug out. The other plugs just seemed to have gas on them when subjected to the high tech smell test. But gasoline has a tendency to overpower the smell of coolant so the seal may be seeping for those cylinders as well.
In any case if I'm going to replace the headgasket I will be able to check the seals across all cylinders once I get her opened up fully.
Before I go through all that trouble I was hoping to get some insight as to any other possibilities that may cause hydrolocking.
Thanks to everyone who's responded so far, I've been testing theories one by one as I read down the list but I thought this new hydrolocking issue should be brought to your attention as it really narrows down the list of possible issues.
 
98GTFan said:
the thing is that there isn't anything preventing the engine from turning, i can crank the engine by turning the crank pulley by hand.
Click to expand...

well, now there is something preventing it from turning.

i vote UIM. the big black plastic snail on top.

i'd replace it before i did the head gaskets. it's VERY likely it's dumping coolant right on top of the cylinders.
 
have you done a compression test yet?

UIM warps and leaks.

LIM gasket fails and leaks.

Headgaskets hardly fail.

Thus compression test.
 
I'll have to work my way down that list after I rent a compression tester from a shop somewhere. Would Upper or Lower intake manifolds also cause compression issues or would the compression test help me to rule out the head-gasket all together?
 


Well then I'll have to run that test tomorrow then get back to you all on that, I really hope its just one of the manifolds because i was seriously dreading replacing the head-gasket. :th_nervous: I just didn't realize that the UIM/LIM could cause hydrolock like that. But it's a good thing I decided to ask.
 
oh yess. my GT hydrolocked from failed UIM. poured coolant inside the engine to the point it was double on oil level and cylinders LOCKED.

see, this was what it did.. http://i96.photobucket.com/albums/l171/BrandonL2000/Grand Prix/IMG_0305.jpg

this happened after 154k ish miles. you have more. so i wouldn't be surprised if this fixed it...of course after removing coolant and changing oil. oh yeah, and new plugs might help after the fact once u get it squared away. or just spray brake clean on the plugs and light it on fire. mine fired right up then lol.
 
You must log in or register to reply here.
Back
Top