Trying to help a member. Mechanical issues, car holding back **UPDATE- Post 28**

Right I have just got back from going around to look at a mates car who is a member on this very forum, and I'm looking for some advise.

Bit of background-

The Car is a L-Reg Toyota Supra SZ with 180k on the clock mix of miles and km so high but not overly bad for a jz.

The Problems-

A few weeks ago the cars alternator failed and a new one was ordered, we installed it and all went well. Only thing noted was when re-bleeding the system (due to removing the top rad hose) The orange Engine management light came on briefly! Shutting the car straight down we fired it back up later and continued the bleed and all was well. We took the car for a drive and all well, temperature sitting perfectly in the middle. He's currently trying to find someone to pull the stored error code, we didn't try the paper clip method.

Now since we did this, the car seems to be taking about 2-3 times longer to get to temperature, the car was re-bled by the owner but the same issue persists. I've suggested another bleed but would have thought is air was in the system we would be seeing increased temperatures? Correct me if I'm wrong please?

Now the main issue, he spoke to me today and said the car seemed slightly down on power and sometimes the throttle response was poor, along with this the idle can fluctuate. (he has had this issue in the past) I fired the car up and the idle was fluctuating slightly when the throttle was blipped, but it soon settled itself out. The ICV was cleaned not long ago too.

The thing is when planting the power in a variety of gears, and in different parts of the rev range, the car holds back for a second or two then jumps to life however this problem is intermittent. Could this be an injector problem perhaps? or sticking throttle body? I've check all the visuals and at first glance everything looks good under there, all fuel lines, vac lines etc.

Anyone have any ideas? should we pull the throttle body of and give it a clean? or clean the ICV again?

Any help much appreciated.

Does it misfire? Could easily be coil pack clips...

Does it misfire? Could easily be coil pack clips...

She doesn't seem to be missing at least it didn't tonight, plus its an NA so its on a dizzy. Could it be the dizzy cap or rotor arm perhaps?

She doesn't seem to be missing at least it didn't tonight, plus its an NA so its on a dizzy. Could it be the dizzy cap or rotor arm perhaps?

Ah right, missed that bit. Could be either. It does sound ignition-related to me, but also could be fuelling. These intermittent faults are a nightmare

Ah right, missed that bit. Could be either. It does sound ignition-related to me, but also could be fuelling. These intermittent faults are a nightmare

Tell me about it, takes a life time to get to the bottom of them. I do have a spare dizzy actually off mine I could pop that on to rule that out.

Any issues springing to life when starting the motor?

Was the thermostat removed?

Any issues springing to life when starting the motor?

It can struggle but never fails. Mainly from cold.

Any issues springing to life when starting the motor?

Occasionally it can, although today it fired up perfectly and sounded lovely on tick over, until I pulled the throttle cable a touch then let it idle. then it was fluctuating.

Was the thermostat removed?

Thermostat is still in place and is working.

It can struggle but never fails. Mainly from cold.

Welcome to your thread

Right, but was it removed?

Right, but was it removed?

Nope, we haven't touched anything cooling wise other than removing the top rad pipe to remove the fan shroud when fitting the alternator.

It can struggle but never fails. Mainly from cold.

Ok, dude. My first port of call would be HT leads. When were they changed last?

Failing that, and I don't want to put the frighteners up you, but a compression check would rule out the head being cooked when you were bleeding the coolant system. I have a compression tester if you guys want to borrow it.

Ok, dude. My first port of call would be HT leads. When were they changed last?

 

Failing that, and I don't want to put the frighteners up you, but a compression check would rule out the head being cooked when you were bleeding the coolant system. I have a compression tester if you guys want to borrow it.

All leads seemed secure at the dizzy end, however may not be soo at the plug end, and as far as im aware they are the originals.

The head wouldn't have cooked when we bled it, it was kept full of fluid and didn't get even close to hot, stayed perfectly in the middle.

However a compression texter could be helpful if all else fails incase there is something more underlying. Thanks Adam

You'd have to get it pretty hot to cook the head gasket. If it's taking 2 - 3 times longer to warm up, it's got to be cooling system related. The ECT sensor will make the car run on choke for as long as it needs in order to make sure it doesn't stall. So basically, it thinks it's cold, "here, have a bit more fuel 'til you warm up." This could also account for lacking power and hesitation on the throttle.

Also, if occasionally it doesn't want to start, it may well be flooding slightly/bore washing the cylinder walls.

Is their warm air coming through the blowers after around 2-3 minutes?

Occasionally it can, although today it fired up perfectly and sounded lovely on tick over, until I pulled the throttle cable a touch then let it idle. then it was fluctuating.

Would be worth checking what voltage the narrow band oxygen sensor is putting out.

Ok, dude. My first port of call would be HT leads. When were they changed last?

 

Failing that, and I don't want to put the frighteners up you, but a compression check would rule out the head being cooked when you were bleeding the coolant system. I have a compression tester if you guys want to borrow it.

They haven't been changed during my ownership so not sure.

I wouldn't know the first thing about doing a compression test. How do you go about doing one with the right tools?

All leads seemed secure at the dizzy end, however may not be soo at the plug end, and as far as im aware they are the originals.

 

The head wouldn't have cooked when we bled it, it was kept full of fluid and didn't get even close to hot, stayed perfectly in the middle.

 

However a compression texter could be helpful if all else fails incase there is something more underlying. Thanks Adam

Original leads.... hmmm... they may look ok, but they will have lost their insulation over the years causing them to contact against the block.

I'm betting leads.

Good luck guys.

You'd have to get it pretty hot to cook the head gasket. If it's taking 2 - 3 times longer to warm up, it's got to be cooling system related. The ECT sensor will make the car run on choke for as long as it needs in order to make sure it doesn't stall. So basically, it thinks it's cold, "here, have a bit more fuel 'til you warm up." This could also account for lacking power and hesitation on the throttle.

 

Also, if occasionally it doesn't want to start, it may well be flooding slightly/bore washing the cylinder walls.

 

Is their warm air coming through the blowers after around 2-3 minutes?

As for the warm air luke will have to chip in I'm afraid on that. We had the blowers on when we bled to air out the first time around, but I know the matrix can be a pig for air locks. Do you think an air lock is fesable with a delayed warm up time?

Would be worth checking what voltage the narrow band oxygen sensor is putting out.

Just do this with a multimetre I take it? I have one in the shed.

They haven't been changed during my ownership so not sure.

 

I wouldn't know the first thing about doing a compression test. How do you go about doing one with the right tools?

If you exhaust all other options, I'll come and give you guys a hand to compression test it to rule out anything nasty.

Just do this with a multimetre I take it? I have one in the shed.

Yes, mate. I haven't done it on an NA, but it should be similar to the TT. There should be a diagnostics box in the engine bay where you can test it.

An ECT sensor can only measure temperature if there's something there to measure. I.e. Water. So it is a possibility. You need to make sure there is definately no air in that system. If possible, park it up over night with the rad cap off and the front of the car pointing up a hill/jacked up. Come back to it and bleed it again, cap off, blowers on hot BUT SWITCHED OFF checking them periodically for heat coming through.

Keep an eye on the temperature gauge, 5 mins it should be in the middle. Air should be warm by that point too. 10 mins in, stick the cap on, make sure the expansion bottle's full up. Keep it running until the electric fan kicks in and then switches off. Also not the temperature of the pipes. The matrix pipes should warm up first.

Yes, mate. I haven't done it on an NA, but it should be similar to the TT. There should be a diagnostics box in the engine bay where you can test it.

Ok mate cheers cant say ive got a clue where than hides, if I find it was setting should I have the meter on, and what reading should we expect to see?

An ECT sensor can only measure temperature if there's something there to measure. I.e. Water. So it is a possibility. You need to make sure there is definately no air in that system. If possible, park it up over night with the rad cap off and the front of the car pointing up a hill/jacked up. Come back to it and bleed it again, cap off, blowers on hot BUT SWITCHED OFF checking them periodically for heat coming through.

I will get it re bled again, I know old big engine jap cars tend to be a sod to get the air out, we did have it on a gradient last time. Think we shall start with a re-bleed and then do the other test too.

I'd definitely do a re-bleed guys, although I would have thought it would be getting hot quick not staying cool but I know very little about such things. I would also definitely change the leads, after doing my own recently I can tell you they were shot, I was amazed the car still ran. Good luck, I hope you guys sort it soon.

Put a new thermostat in it as a matter of course, read the code that triggered the MIL light. Forget bleeding it again, people are obsessed with bleeding these things Plug leads can be tested with a 3 quid multimeter, and looking at them for HT breakdown at night. I havve yet to see a 2JZ-GE cap that's tracking, or a rotor arm.