Rough Idle Crap (1 Viewer)

[hygge]

After having recently installed a number of things, I am trying to diagnose what the F is up with my FJ62 truck.

First, what I have done recently.

Over the last two months the truck was out of commission. I replaced the side cover gasket ( which meant that I took out the distributor, air intake.

I replaced the fuel filter.

Then since, I was at it, I changed the oil pan gasket.

I also replaced the Exhaust ( and Intake) Manifold Gaskets. To get to these, I had to take off the Air Plenum/Throttle Body and the injectors.

During this time, I decided to have the fuel injectors and cold start injector's cleaned by Witch Hunter Performance.

I decided to replace all of the old vacuum hoses too, cause why not.

When I put everything back together, I was very careful to put the distributor back in exactly as I had taken it out ( I took lots of pictures and marked both the distributor cap and the rotor.

Now after all of my hard work, I am having trouble with the truck running.

I can drive it down the street and I went to the market over the weekend. But when I hit a stop sign or a long red light, the truck stalls or it idles really really rough.

See videos below:




I've read about resetting the ECM. Is the ECM the same as an ECU?

From what I gather you pull the fuse out for 15 seconds to a minute. I also read that disconnecting the battery will also reset the ECU. I've taken the fuse out for 10 minutes. And I still get this crappy idle.

There are no check engine lights.

Also, when I put the car into Park ( which is what I am doing at stop lights), the engine idles at around 1,000 RPM, but if I stop the truck and keep it in drive it hovers around 500-800 rpm.

So Mudders - What am I doing wrong?

1. Its ECM/ECU issue?

2. Distributor and timing is off?

3. Something else...

Before I did all of this crap to the truck, it was actually working just fine. I had taken it into Mudrak and had them give me a list of maintenance repairs. Being overly ambitious, I decided that I wanted to take on all the work and not have Mudrak do it for me.

Any help would be awesome!!

Thank you!

Sawdust's Overlord

 

[Seth_O]

How much driving have you done since resetting the ECM? On my wifes sequoia I have to drive both street and freeway, probably 15-30mins for the ECU to relearn the map. Until I do it will die at stop signs and idle really low.

Have you checked vacuum? It could be a vacuum leak.

 

[portlandcruiser]

No advice, but I’m going to follow. I havevrough idle and low vaccine issues with my 62.

 

[hygge]

How much driving have you done since resetting the ECM? On my wifes sequoia I have to drive both street and freeway, probably 15-30mins for the ECU to relearn the map. Until I do it will die at stop signs and idle really low.

Have you checked vacuum? It could be a vacuum leak.

I have driven it to the grocery store, so not more than a 15 minute drive, but with weekend traffic, there were a good 6-8 stop lights that I hit. But no, have not taken it to freeway speed yet or driven for a solid 15 minutes or longer. Only around my neighborhood and the store.

I've checked all the vacuum hoses that I replaced (they look damn sexy), but I don't see any falling off or pinched. Could be worth a third look.

Thanks for the advice of driving around for the ECM to reset. I don't know if its an hour of driving or 10 minutes for the truck to get reacclimatized.

 

[AussieHJCruza]

Sounds vacuum leak-ish to me too - the air intake hose from the airbox isn't cracked or something is it?

 

[morganism]

In some other Toys, you have to pull the batt cable, then turn key to ON position to reset.

Lookup the "readiness monitor" for your cruiser series too, will tell you how long you have to drive to set the comp. Dont know if your series needs this tho.

Toyota/Lexus OBD-II Drive Cycles | Car OBD Diagnostics, ECU Chip Tuning & Auto Repair Support

SMOG Readiness-Catalyst Monitor

Do you still have an EGR valve ? Stuck open can cause this symptom too.

 

[hygge]

In some other Toys, you have to pull the batt cable, then turn key to ON position to reset.

Lookup the "readiness monitor" for your cruiser series too, will tell you how long you have to drive to set the comp. Dont know if your series needs this tho.

Toyota/Lexus OBD-II Drive Cycles | Car OBD Diagnostics, ECU Chip Tuning & Auto Repair Support

SMOG Readiness-Catalyst Monitor

Do you still have an EGR valve ? Stuck open can cause this symptom too.

The EGR does not appear to be stuck open, but that is an interesting thing to look at.

Did FJ62's have readiness monitor? I did look it up but did not find anything.

The link you gave is for 1996 and later, but that's not applicable to a 1989.

Thanks for the thoughts!

 

[hygge]

Sounds vacuum leak-ish to me too - the air intake hose from the airbox isn't cracked or something is it?

I went with a fine tooth over all my vacuum hoses and air intake. The Air Breather hose #2 that connects to the throttle body was replaced three months ago. When I reinstalled the air intake, I made sure that everything was on tight.

Only thing I can think of is leaks in the Intake Manifold - I recently replaced the gasket ( when I was replacing the exhaust manifold gasket). Everything is torqued down fairly solid, so this should not be the issue.

 

[hygge]

How much driving have you done since resetting the ECM? On my wifes sequoia I have to drive both street and freeway, probably 15-30mins for the ECU to relearn the map. Until I do it will die at stop signs and idle really low.

Have you checked vacuum? It could be a vacuum leak.

I have rechecked the vacuum hoses, they are all on rock solid and they are all brand new, since I replaced with silicone from Boost Controller two weeks ago.

I drove the truck on the freeway about 20 miles and on the city streets for an hour. Its still stalling if I hit a red light.

On the freedway it is taking longer to get up to speed. I tried to go up a steep hill and the speed went down to 10mph. I was fairly surprised.

Seems to cruise once up to speed, but its the getting up to speed that is taking longer than before I did all of these "improvements".

 

[Rustic76]

Have you put a vacuum gauge on it yet and checked to see what kind of vacuum numbers you have. Could help rule out a vacuum leak somewhere.

Also, did you recheck the timing after you reseated the dizzy?

I had a similar episode one time in my 60 when I replaced all my vacuum lines. It seemed to run fine but would want to stall out when I came to a stop. I swapped around the purge and tank lines on the charcoal canister and it solved the issue.

 

[Hojack]

Try using a propane torch. Use only the gas (no ingnition) around the vacuume line while the engine is idling. The motor should smooth out when you’ve found the leak.

 

[hygge]

Try using a propane torch. Use only the gas (no ingnition) around the vacuume line while the engine is idling. The motor should smooth out when you’ve found the leak.

This sounds like an interesting way to take a look at potential leaks. I watched Ericthecarguy's video and it seems pretty straightforward. I'll check this out this weekend.

It would make sense that its a vacuum leak since I did replace the intake manifold gasket AND all the vacuum hoses.

Thanks !

 

[hygge]

Have you put a vacuum gauge on it yet and checked to see what kind of vacuum numbers you have. Could help rule out a vacuum leak somewhere.

Also, did you recheck the timing after you reseated the dizzy?

I had a similar episode one time in my 60 when I replaced all my vacuum lines. It seemed to run fine but would want to stall out when I came to a stop. I swapped around the purge and tank lines on the charcoal canister and it solved the issue.

Did not recheck the timing after resetting the dizzy. I'll have to figure out how to do that - never done it before.

Also, don't have a vacuum gauge and never used one before - but sounds like that could be helpful for this particular issue and future diagnosis.

Thank you for the suggestions!

 

[Rustic76]

Did not recheck the timing after resetting the dizzy. I'll have to figure out how to do that - never done it before.

Also, don't have a vacuum gauge and never used one before - but sounds like that could be helpful for this particular issue and future diagnosis.

Thank you for the suggestions!

Go out and get a timing light and vacuum gauge. Both are cheap and very necessary to have around the shop.

 

[NeverGiveUpYota]

Innova timing light w/ digital readout on Amazon about $70. Vac gauge is about $20.
You can hit the manifold gasket mating surface w/ small spritzs of carb spray (same as propane) and if RPMs rise and settle you’ve found your leak. Stay away from distributor area.

 

[morganism]

Did you disconnect the brake booster hose when you did the exhaust? Major vac there.

Voltage looks low on the dash picture too. Did you replace the block to firewall ground ?

Still think you need to check the EGR, by using a spare piece of longish vac hose.

Idle till warm, and put a piece of vac hose on the tophat. Suck quickly on the end, it should almost stall. Do a few times, and listen for rocks rattling down the pipe. this will last a couple years, then have to do it again. If no change, it may be welded open on a rock, and will have to replace.

EGR or no EGR?

Vacuum test steps (with video)

 

[hygge]

Innova timing light w/ digital readout on Amazon about $70. Vac gauge is about $20.
You can hit the manifold gasket mating surface w/ small spritzs of carb spray (same as propane) and if RPMs rise and settle you’ve found your leak. Stay away from distributor area.

Something like this for vacuum gauge?

Lisle 20300 Vacuum Gauge and Fuel Pump Tester https://www.amazon.com/dp/B000CODRFO/ref=cm_sw_r_cp_apa_F7ajBbRVK5DK0

I found the digital Innova timer for $74.95.

Amazon PRIME!!

 

[Hojack]

Gotta love Amazon Prime

 

[NeverGiveUpYota]

And yes, exactly both those.

 

[hygge]

And yes, exactly both those.

Both are being Primed over to me from my friends over at Amazon.

In the meanwhile, I look forward to trying the propane vacuum test, with a friendly fire extinguisher by my side.