98 Camry idle problems. Help please!!!

[Michael Wolfe]

Hi all,
I am working on my fiance's 98 Camry V6 3.0. It idled and ran great, but had an oil leak and a slow head gasket leak, so over Christmas I pulled the engine replaced a bunch of oil seals, had the heads machined, and replaced the head gaskets.

Got the car back together fine, but can't get it running right. It kept dying at idle unless I revved the motor to above 1200 rpm. If I rev the motor up to 2500 rpm it cuts out instantly. Does not sputter and die, but cuts out like an electrical problem.

Read a lot about problems with the IAC sensor being dirty, so I removed the throttle body and cleaned the throttle body and IAC valve, but problem is the same. With the IAC out, I verified that the valve was opening and shutting by grounding the different leads while attached to 12V per the Haynes manual.

I also read about the ECM having to relearn the idle speed, so I cleared the computer with a code scanner (it was showing misfire codes p300, p301, and p304), and maintained the idle high enough to keep the car from dying. After about 5 minutes the idle on its own fluctuates between 1400 and 1600 rpm without me holding the gas at all anymore. Let it run for five more minutes without touching the gas and it held steady on its own from 1400-1600 rpm.

Does this mean the computer has relearned at a high idle?

If I try to put the car in gear from this high idle, the rpm drop and the car dies. Still if I raise the RPM to 2500 it cuts out.

Any ideas where to start looking? After I cleared the misfire codes and ran the car for ten minutes, no new codes appeared. Should running the car for ten minutes be long enough to generate a MIL code?

[Chris Crash]

My car just relearned the idle, too, after reinstalling the engine. It idled about 3500 at first, then a few minutes later, about 2000, and now it's at a normal level.

[fenixus]

sound like you have a serious vacuum leak which leans fuel mixture to hell, hence why ECU adjusts the RPM very high to compensate (also gives much more fuel at same time). make sure there is no vacuum hose disconnected (or wrongly connected) anywhere.s

[Michael Wolfe]

Any place I could get a vacuum diagram for this car?

[BMR]

There should be a vacuum diagram in the engine bay; on the underside of the hood I believe.

[Michael Wolfe]

Thanks for the responses. I checked all the vacuum lines and they are correct and unobstructed.

I did notice that my original post was slightly incorrect. The car is not holding an idle as I stated in the original post, I did not realize that last night my friend adjusted a screw holding the throttle open @ 1400 RPM. The computer did not learn a new idle.

I ran the car for about 20 minutes today and couldn't get any codes to show up.

Bottom line is, the car only runs if I hold the throttle to between 1200 and 2500 RPM. Otherwise, it dies.

Never been so stuck on troubleshooting before. Would appreciate any ideas.

[JohnGD]

So below 1200 and above 2500 it just cuts off like you turn off the key? Does it do this (>2500rpms) in P/N or only in gear?

Maybe double check electrical connections, including cam and crank sensors?

[Michael Wolfe]

It cuts out in P/N below 1200 and above 2500. I can't put it into gear. If I try to put it into gear, the RPM drops and it dies.

I checked the resistance on both sensors and they are within spec according to Chilton's manual. Any other checks I should perform on crankshaft or camshaft sensor besides resistance checks?

[fenixus]

wondering why it doesn't give a code if something is so wrong that engine stops at normal idle or on moderate acceleration ... timing?

[JohnGD]

Yeah, I was wondering about that. I'd probably go back and check the timing area - cams and crank and sensors. Double check all electrical connections. These are magnetic pickup sensors, so they send signals as the engine turns, it's more than you can measure with a meter when off.

[Michael Wolfe]

No kidding, I am at the point where I would be happy for an engine code to show up.

Are these symptoms indicative the timing is off?

This is the first time I removed the cams on a dual overhead cam, but I think I got it right. I marked the cams for each head and then when I got the heads back from the machine shop I put them back in and lined up the dots on the cam gears.

Used a compression gauge in #1 and lined up the crank with the mark on the oil pump at TDC. Lined up the timing marks on the crank and two cam sprockets, pretty confident the belt is correct.

I never like throwing money at a problem I don't understand, but I might be to that point. I have checked all the electrical connections several times. If there are no other checks other than resistance checks, between the camshaft and crank sensor, is there any idea which I should try to replace first?

[JohnGD]

Don't throw money at replacing parts. I was thinking maybe something is causing the cam/crank sensors not to generate the proper signal for ignition. I don't think the sensors themselves are bad, because these are simple magnetic pickups. So don't change the sensors unless they are bad.

If your timing marks line up you should be fine. Just want to make sure, you lined up the crank mark at 0 TDC (oil pump) and the the cam sprockets lined up with the marks on the back plate (not just the two dots on the gears on the driver side)? On these engines the compression gauge is not needed really.

And the plug wires are at the right cylinders and the vacuum reserve tank with in/out ports are correctly connected? I'm guessing too.

Originally Posted by Michael Wolfe

This is the first time I removed the cams on a dual overhead cam, but I think I got it right. I marked the cams for each head and then when I got the heads back from the machine shop I put them back in and lined up the dots on the cam gears.

Used a compression gauge in #1 and lined up the crank with the mark on the oil pump at TDC. Lined up the timing marks on the crank and two cam sprockets, pretty confident the belt is correct.

I never like throwing money at a problem I don't understand, but I might be to that point. I have checked all the electrical connections several times. If there are no other checks other than resistance checks, between the camshaft and crank sensor, is there any idea which I should try to replace first?

[JohnGD]

BTW, the 1MZ are know for coolant seepages at the head gasket. Was this the problem?

Also, did the head bolts seize to the block or cause thread problems because of coolant seepage?

[Michael Wolfe]

When reinstalling the cams into the heads I lined up the double dots on the drivers side gears of the cams.
When I installed the timing belt, I lined up the cam sprockets with the notches on the timing cover backing plate.

There was an oil leak I couldn't pinpoint probably on the oil pump seal or the front crank seal, we had to add a quart almost once every two or three weeks.
Not sure what coolant seepage is, but the head bolts did not give any problems when I removed them, and I replaced them with new ones. My problem was the coolant level was dropping slowly, so we would have to add about 12 ounces every couple weeks. The reservoir would stay full (no suction) and there was no visible coolant leak, so I figured the head gasket was leaking and it wasn't sucking out of the reservoir, so I decided to replace oil seals, get the heads machined, and replace the head gasket over the holidays.

Is the vacuum reserve tank the one under the battery? The two lines out of that are connected properly per the diagram on the hood of the car.

Like I said earlier, I checked the resistance across the IAC valve and removed the valve and tested it with a 12V battery on the bench and it opened and shut. Does this mean for sure the valve is OK?

[JohnGD]

Then your timing belt should be fine.

IAC - I doubt it will cause engine cut offs like that. However, the right way to clean is: DIY removal & cleaning of IAC

Coolant loss - could be near the water pump (pump or gasket)? Or external coolant seepage from the headgasket out. It's a common problem. You'll see white coolant deposites there.

Yes, the reserve tank is under the battery. One port is in and the other port is out. The hoses need to go to the right ports.

Otherwise I don't really know at this point.

Originally Posted by Michael Wolfe

When reinstalling the cams into the heads I lined up the double dots on the drivers side gears of the cams.
When I installed the timing belt, I lined up the cam sprockets with the notches on the timing cover backing plate.

There was an oil leak I couldn't pinpoint probably on the oil pump seal or the front crank seal, we had to add a quart almost once every two or three weeks.
Not sure what coolant seepage is, but the head bolts did not give any problems when I removed them, and I replaced them with new ones. My problem was the coolant level was dropping slowly, so we would have to add about 12 ounces every couple weeks. The reservoir would stay full (no suction) and there was no visible coolant leak, so I figured the head gasket was leaking and it wasn't sucking out of the reservoir, so I decided to replace oil seals, get the heads machined, and replace the head gasket over the holidays.

Is the vacuum reserve tank the one under the battery? The two lines out of that are connected properly per the diagram on the hood of the car.

Like I said earlier, I checked the resistance across the IAC valve and removed the valve and tested it with a 12V battery on the bench and it opened and shut. Does this mean for sure the valve is OK?