Another head gasket thread

[MindBender0001]

If compression checks out good I would switch ecm..very easy to do, in the passenger kick panel. He probably meant ecm..not icm.

I'm still waiting for compression tester to get here. If it's an easy swap, maybe I'll just try it. Both rigs are exact same trim/engine/tranny and now that the '93 is back together and running, the ECM and the ICM should be pretty easy diagnosing swaps.

 

[MindBender0001]

If compression checks out good I would switch ecm..very easy to do, in the passenger kick panel. He probably meant ecm..not icm.

The ICM he was talking about and posted pics of is behind the battery. Already put eys on it in both rigs. Intersting to me is on the '92 the SPOUT is between the fuse box and firewall, but the '93 has it right there with the ICM behind the battery. Amazes me the suttle differences one year makes...

By the way, I tried to find the common ground for the injectors you were curious of. Voltmemter to battery ground and continuity to injector pins gave me no tone. Stopped there. Did notice that all of the passenger injector wires are the same (inj to inj) but different pass to drv.

 

[jd4242]

The ICM he was talking about and posted pics of is behind the battery. Already put eys on it in both rigs. Intersting to me is on the '92 the SPOUT is between the fuse box and firewall, but the '93 has it right there with the ICM behind the battery. Amazes me the suttle differences one year makes...

By the way, I tried to find the common ground for the injectors you were curious of. Voltmemter to battery ground and continuity to injector pins gave me no tone. Stopped there. Did notice that all of the passenger injector wires are the same (inj to inj) but different pass to drv.

Thats not a icm..its a edis box..think he just made up the word icm..because it is the ignition control module but real name is edis..

 

[jd4242]

And doubt thats your issue if your getting spark..who knows tho

 

[jd4242]

There should be two spout connectors on both rigs..only one controls timing tho..(one near fuse box)

 

[MindBender0001]

NM on the SPOUT...both rigs have two??? K. THAT thing. Swapped it over. '93 still good. How does it ground? While taking it off the '92 I noticed it was loose...

 

[jd4242]

NM on the SPOUT...both rigs have two??? K. THAT thing. Swapped it over. '93 still good. How does it ground? While taking it off the '92 I noticed it was loose...

""Should""have two..

I believe there is a ground bolt right above it..cant remember exactly off top of my head tho..I still say switch ecm...you should be getting a code if its running that bad unless the ecm is causing it to run that bad..especially now your pretty certain all the engine sensor are good..

 

[MindBender0001]

Do I just keep loosening the bolt on the ECM connector to pull it off or is there a clip also holding the connector? The bolt backs out easily for a bit, then gets hard. This I don't wanna break!!!

 

[MindBender0001]

""Should""have two..

I believe there is a ground bolt right above it..cant remember exactly off top of my head tho..I still say switch ecm...you should be getting a code if its running that bad unless the ecm is causing it to run that bad..especially now your pretty certain all the engine sensor are good..

Since I cleared the codes, how long would it have to run like this to throw codes again?

 

[jd4242]

Would have to run till warm or think 15 mins..dont quote me on 15 tho..basically it needs to leave open loop.


Yes I believe its just the bolt..the harness is pretty hard to pull out tho.

 

[MindBender0001]

One 5.5mm and one 10mm. Computers swapped. '93 still good. My DIY compression tester is a no-go. Dude brought me a 20psi gauge.....

 

[MindBender0001]

Called guy I bought it from. He's thinking my valves aren't seating. Think I'm gonna pull heads and put in new valves. He's got the equipment to do a proper valve grind and offered to do it for free. I'm still gonna do a compression check before I actually pull the heads. He told me again that he did a compression test on it and said all six were within 10psi of each other and they were all 160-170psi, no oil.

 

[MindBender0001]

So now I'm freaking a little bit. I'm on RA looking at the valves...they list two different stem diameters, and I didn't measure the stock ones while they were out. I know a couple of the valves seemed maybe a thou or two over spec, but not .015"!!! I'm trying to price this stuff out and now I don't know which valves to get...

 

[MindBender0001]

Or I COULD just go with these:

http://www.ebay.com/itm/90-01-Fits-...iter_Display:4.0L&hash=item2335dbe3fd&vxp=mtr

 

[MindBender0001]

Compression test done. Started on 4, 5, 6. Then moved to 1, 2, 3. The instructions that came with the tester say to check the first and fourth 'puff'.

Cyl:First 'puff'-Fourth 'puff'
4:80-145 First run (Didn't see enough variance to run more)
5:70-145 First run (Didn't see enough variance to run more)
6:95-155 First run
75-140 Second run
70-145 Third run

1:90-145 First run
80-150 Second run
70-140 Third run
2:90-140 First run
80 Second run (Battery died. Even with jumper cables, I couldn't spin it fast enough to finish test)
3:0 (Jumped battery from other x. Spins like no plug; valves move)

From what I see, all looks good (other than #3). With ZERO compression in 3, I don't know how to determine between valves/rings/gasket. Either way, pull heads, grind valves, and re-install?

Just for the record, the exhaust pushrod on #3 is the one i was having issues with...that lifter is the one that was missing the plastic cone and gave me some trouble getting the pushrod in the right spot...could the pushrod still not be in the right spot and holding the valve open?

 

[natenkiki2004]

Easy to check the pushrod, pop the valve cover off for that cylinder and take a peek. To see 0, it would almost have to be a valve being held open or you didn't get a good seal on the compression tester. Everybody else looks great. Nice and even with good values.

For what it's worth, the only compression test rules that I follow are to crank the engine over without spark plugs and only stop when the needle stops rising. Then take the reading. Relieve pressure and perform again.

 

[MindBender0001]

The covers are already off, that's how I can verify the valves are moving. I guess my issue with the pushrod is this: if I'm missing the cone on that one lifter, is there any possibilty (bear in mind this ain't my first top end rebuild), that the pushrod could be sitting ON the lifter, but not in the seat? The valve would move, yes, but it could keep it open? Lift on the cam is just over 1/4"...if memory serves there's a good 1/8" difference between the actual lifter seat and the groove between the seat and outer body...if my pushrod (for whatever reason) was in that groove instead of the seat, the valve would still open, but not close fully....I'm gonna go double check the compression tester now that the battery is charged.

 

[MindBender0001]

Don't know how to explain this, but I'll try. Just went out and checked the tester and it's in all the way. While turning the engine over, I could see the UIM gasket 'moving'. When I put my hand over each runner while turning engine over, I don't feel anything. When I get to the intake runner for #3 (same one with pushrod question), I can feel air moving in and out from each stroke.....almost like it's making compression but it's coming back up through intake......

 

[MindBender0001]

I need to correct a previous post. The pushrod in question is the INTAKE on #3 , NOT exhaust. But still....why is my compression coming back up into intake, and only on #3 ?

 

[MindBender0001]

After drawing this out on paper, my compression is going past the intake valve on #3 and blowing out the intake. Short of the pushrod being in the wrong place, bad seat/valve interface. Trying to come up with an accurate way to measure #3 intake valve open/closed position as compared to any of the other 5...maybe I'll borrow a magnetic dial indicator from work. I'm ok with pulling the heads again, but if I don't HAVE to....