AGreen

Don't listen to parts guys. There's a reason they sell parts and don't install them. They're retards with enough knowledge to be dangerous.

There is no choke on an injected engine. The car not starting because of a faulty ECT sensor could have been a possibility back years ago, but the ecu will see that the voltage is out of range and go into failsafe mode and use a standard reference temperature, usually around 75 degrees F. Sensor voltage is normally .5v to 4.5v, and when it faults it will either open and the ecu will read 5 volts, or short and the ecu reads 0v. 75 degrees F is about the right temperature for your car to start, so it will actually start, run ok, then be really hard to start when hot.

Get crackin' on that diagnostic! fing02.gif

97DerekTiburon

Thanks man. I knew "choking" wasn't the right term but hey, he was talking about his late 80's Camaro so I let it slide smoker.gif

I'm amazed at some of you guys. You sound like Professors of Automotive Technology here. And sometimes I think I know my way around cars... Until I have problems like this and need to ask for help.

Where else would I turn if not for this place, huh?

I may be able to get compression readings tomorrow (Wed.).

Ericy321

Im just going through what I do when I get a car in like this.

AGreen

Same here. I worked on cars and made a living off it for over 3 years. Now I'm working in nuclear technology.... so if some of the information is a bit much at times, don't be overwhelmed.

Take note that all spark plugs should be removed for a compression test.

If the compression readings aren't right, try squirting some regular engine oil (just a little squirt) into the spark plug hole, and then retry. I don't think the rings went out on you suddenly, but if by chance fuel were dumping into the cylinders, it will wash away the oil film on the cylinder wall and reduce compression drastically.

97DerekTiburon

Figures are before and after the oil squirt. (#1 is driver' side)




#1) 120 now 125

#2) 80! now 120

#3) 180 now 200

# 4) 190 now 210


OK, now what? From the looks of things, timing belt slip? Just a guess!

AGreen

take off the timing cover and valve cover, and check the timing. Go on HMA and read up on how to verify the timing is right.

If everything is good (and at by looking at those numbers) I'd say you have a blown head gasket. Since numbers 1#2 are low, the head gasket is probably blown between the 2 cylinders. Which makes sense, if you think about it. When the engine warmed up, the hole probably sealed itself to where you didn't experience much problem with it. Did the car ever overheat on you?

97DerekTiburon

No, never overheated. But it's never (in my hands) been run in over 40 degree heat.

I will say that I have clean oil on the dipstick if THAT means anything. I guess if it's blown between cylinders, the coolant in the oil wouldn't be an issue, correct?

So you think the timing may be ok, or if it is ok, the next step is a head gasket?

I remember reading that a head gasket is not too bad a job. I'm better at fixing things like that than I am at electrical diagnosis.

AGreen

Right-o on all accounts. The oil-in-coolant is only an issue (generally) if you've only got one low compression number. If the timing's ok (which it's leaning more towards that), then the next step is probably a head gasket. A quick rule of thumb for checking compression that I forgot to mention before is that if the compression numbers are off by 15 percent between the highest and lowest reading cylinders, then it's out of spec and needs repair. So if cylinder 4 is 100%, you're looking at a 59% difference between it and #1, 57% at #2, and 95% at cylinder 3.

Replacing a head gasket isn't too bad of a job. It can be done this weekend with basic hand tools, and maybe a drill with a scrubby pad for cleaning the head and block. Since the timing belt and valve cover have to come off for the head gasket anyways, you might as well pull those to verify the timing's on.

97DerekTiburon

I have a question or two.

1) Why exactly would a blown head gasket between cylinders cause the engine to not start at all? I would think that it'd run awful or start and quit with ugly sounds.

2) If 2 cylinders were "equalized" due to being "connected" via a leak in the head gasket, wouldn't the compression figures be equal between the two?

I suppose 120 and 125 may be close enough but I would think that I would have very little to no compression in either cyl #1 or 2 seeing that the adjacent cylinders' spark plug is out releasing all compression in both cylinders. See what I mean? I'm thinking that the failed gasket would effectively make one double-sized cylinder.

97DerekTiburon

If the head gasket IS the problem and it needs to be replaced, is there something I should do with the head performance-wise like a 3 agle valve job or a slight milling to up compression slightly? Open up the intake or port-match?

If so, any numbers would be very much appreciated such as angles on the valve job or mm of milling the head etc.

I plan to keep this NA so keep that in mind.