Missfiring engine
Thread Starter
Cruising
Joined: Oct 2011
Posts: 13
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From: Ft Lauderdale FL
Missfiring engine
Here’s my problem
Any help would be good.I blew a radiator hose several weeks ago engine stopped, I changed the hose and drove home no problem. Four days later engine stopped would not start I presumed it was the Opti I replaced the cap and rotor new plugs, engine ran but missing and coughing back firing so presumed the opti was out of timing so removed opti checked my work and reinstalled everything so for the third time I did it again this time I replaced the distributor with MDS unit installed new coil and crank shaft sensor and still no start used easy start and engine fired for short time dst were P0100 and pins connection under wheel were showing H64 and H65 checked fuel pressure again and now has no fuel pressure but had it before, so replaced fuel pump and filter (now have good fuel pres) but still missing and showing still P0100 ran car around the block it appeared to have some oil sprayed from area of cyl 6-8 now could not identify where from, changed oil and filter when I removed oil cap there was water impregnated oil on cap so presumed it was possibly a head gasket today removed all spark plugs and did compression test all cylinders were 150 psi removed valve cover on passenger side and water in oil impregnated that had been there for some time also drops of clear water on valve rockers ?? also some clear water in breather pipe.
Is this water condensation or possibly left over from the original hose burst? Seem strange that it was clear clean water droplets and the yellow oil seems to be rather old.
Ray
Any help would be good.I blew a radiator hose several weeks ago engine stopped, I changed the hose and drove home no problem. Four days later engine stopped would not start I presumed it was the Opti I replaced the cap and rotor new plugs, engine ran but missing and coughing back firing so presumed the opti was out of timing so removed opti checked my work and reinstalled everything so for the third time I did it again this time I replaced the distributor with MDS unit installed new coil and crank shaft sensor and still no start used easy start and engine fired for short time dst were P0100 and pins connection under wheel were showing H64 and H65 checked fuel pressure again and now has no fuel pressure but had it before, so replaced fuel pump and filter (now have good fuel pres) but still missing and showing still P0100 ran car around the block it appeared to have some oil sprayed from area of cyl 6-8 now could not identify where from, changed oil and filter when I removed oil cap there was water impregnated oil on cap so presumed it was possibly a head gasket today removed all spark plugs and did compression test all cylinders were 150 psi removed valve cover on passenger side and water in oil impregnated that had been there for some time also drops of clear water on valve rockers ?? also some clear water in breather pipe.
Is this water condensation or possibly left over from the original hose burst? Seem strange that it was clear clean water droplets and the yellow oil seems to be rather old.
Ray
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
On my car the plastic part of the radiator that the hose connects to broke off (not a Corvette). Later I noticed oil running down the side of the block, coming from where the block and head join -- blown head gasket.
It sounds like what you have here. A head gasket can blow between the water and oil passages without affecting the compression.
When the head gasket on my '86 blew, it broke out into the cylinder (lucky #7). I saw water coming out of the spark plug hole when I did a compression check.
It sounds like what you have here. A head gasket can blow between the water and oil passages without affecting the compression.
When the head gasket on my '86 blew, it broke out into the cylinder (lucky #7). I saw water coming out of the spark plug hole when I did a compression check.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
World's longest run-on sentence? 
Year?
Engine?
Transmission?
Part of your post suggests it's a '96 such as mentioning the crank sensor (which by the way has absolutely nothing to do with how the engine runs on a '96, it is for misfire detection only) yet you also mention OBD 1 style codes "H64, H65". These are history codes and probably from the CCM since you can't pull PCM codes from a '96 using the paperclip method.
What is "dst"? DTC is diagnostic trouble code. dst is typically short for distributor.
Most likely, if you blew the hose and ran the engine so long that the engine stopped, at a minimum you blew a head gasket and/or cracked one of the cylinder heads.
Buy a factory service manual. It would have already paid for itself based on the number of parts you've thrown at the problem.
Year?
Engine?
Transmission?
Part of your post suggests it's a '96 such as mentioning the crank sensor (which by the way has absolutely nothing to do with how the engine runs on a '96, it is for misfire detection only) yet you also mention OBD 1 style codes "H64, H65". These are history codes and probably from the CCM since you can't pull PCM codes from a '96 using the paperclip method.
What is "dst"? DTC is diagnostic trouble code. dst is typically short for distributor.
Most likely, if you blew the hose and ran the engine so long that the engine stopped, at a minimum you blew a head gasket and/or cracked one of the cylinder heads.
Buy a factory service manual. It would have already paid for itself based on the number of parts you've thrown at the problem.
Thread Starter
Cruising
Joined: Oct 2011
Posts: 13
Likes: 0
From: Ft Lauderdale FL
missfire
The year is a 96 engine LT4 six speed manual
the car ran aproxamatley less than 5 minutes before I stopped it after changing the hose I drove the car for 4 days and one day it would not start however after several attempts it did but next day definitely would not start.
While the car was in pieces i decided to change the crank sensor anyway now car runs but has miss all comp are 150 but still have code P0100. I did find considerable condensation under valve cover but I believe its due to the humidity her in florida. I have installed a new complete MSD Distibutor and found that fuel presure was zero as it had been droping off in the past I installed new pump and filter also new coil and plugs as well as oil change sorry DTC for codes and dst for distributor.
Ray
the car ran aproxamatley less than 5 minutes before I stopped it after changing the hose I drove the car for 4 days and one day it would not start however after several attempts it did but next day definitely would not start.
While the car was in pieces i decided to change the crank sensor anyway now car runs but has miss all comp are 150 but still have code P0100. I did find considerable condensation under valve cover but I believe its due to the humidity her in florida. I have installed a new complete MSD Distibutor and found that fuel presure was zero as it had been droping off in the past I installed new pump and filter also new coil and plugs as well as oil change sorry DTC for codes and dst for distributor.
Ray
Intermediate
Joined: Sep 2006
Posts: 38
Likes: 1
You need to work the P0100 code which relates to the mass airflow (MAF) sensor and related circuitry. A Factory Service Manual (FSM) will help greatly with this. Check the condition of the wires and the seating of the connectors for the wiring that leads up to the MAF.
While your at it use a spark plug tester to verify that you have a strong and consistent spark at both the coil and each cylinder. Double check that the wires are routed correctly.
A cylinder leakdown test will help you determine if there was any damage done due to overheating.
It would also be a good idea to verify that the injectors are operating properly. There are electrical tests etc that will be explained in the FSM
While your at it use a spark plug tester to verify that you have a strong and consistent spark at both the coil and each cylinder. Double check that the wires are routed correctly.
A cylinder leakdown test will help you determine if there was any damage done due to overheating.
It would also be a good idea to verify that the injectors are operating properly. There are electrical tests etc that will be explained in the FSM
Thread Starter
Cruising
Joined: Oct 2011
Posts: 13
Likes: 0
From: Ft Lauderdale FL
miss
The MAF was also replaced and I do have good ground and voltage there. I would like to know where the actual wires come of the PCM, RED/GREY terminals etc, so I can check them.
Good idea on the cyl leak down tester I have no water in oil or oil in water and compressions are good I will check the injectors as per FSM plug wires are correct and I have spark at the plugs the motor runs but has this crazy miss. Not worth driving.
Good idea on the cyl leak down tester I have no water in oil or oil in water and compressions are good I will check the injectors as per FSM plug wires are correct and I have spark at the plugs the motor runs but has this crazy miss. Not worth driving.
