99 4runner 3.4 P1300

[jti30666]

Ok so here is what I got....

A friend of mine brought his runner (181K ODO) to me after buying it saying that it feels like its missing...

At first my scanner showed no codes but it definitely has a miss between 2k-3k but after driving it home the P1300 (ign circuit #1) showed up...

Anywhere above or below that mark it runs ok...

I started with the basics first and this is what I have done:

fuel filter (old was clogged)
Fuel pressure is within spec per FSM
new plugs OEM (old plugs were INCORRECT not even the correct part#)
new wires OEM
timing ok (verified 4 times); belt/components are actually "new"
compression good/leakdown test passed
all fluids not contaminated
pressure tested cool sys passed
tested coolant passed
disconnected exhaust w/ no change

Still no change...I went ahead and tested the TPS, MAF, cam, crank etc and all passed..

Ohm tested all coils and they are good, even put a new one on no. 1

I verified however that I'm getting spark on both plugs controlled by coil no.1...And verified no dead spots in harness

I then went to the test procedure for igniter and ecu...I'm getting the 5V at the IGF connector on ecu so the flowchart states to replace the igniter...

I replaced the igniter with one from a friends junkyard with no change...interesting though the donor had almost every sensor on it replaced so they might have been chasing a similar problem...It could be bad so ill try and pick up a few more today

Any suggestions....

 

[jti30666]

One possibility that could be causing this is either the ecu or igniter is not adjusting the "spark timing" correctly with rpm ranges where its missing...ie the gap between the spark intervals has flat spot between 2k - 3k

 

[TheDurk]

The only thing I would say that is I would not take the presence of the IGF signal as a definite unless you are checking it WHILE the engine is missing. It could still be a defect in the ECM which is where I would go next if a known good igniter does not resolve the issue. You can't diagnose a fault if the fault is not occurring while you are diagnosing.

Are you able to read the freeze frame data saved with the P1300 DTC? Maybe that will help you recreate the fault so you can chase it...

Intermittent faults are a pain.

 

[jti30666]

the igniter that I installed is from a junkyard donor so I do not know if its technically good..

Freeze frame data isn't showing me a misfire or anything out of the ordinary...

Actually all of the scans, live data, etc are telling me that everything is OK but yet I'm still pulling a P1300...

I'm starting to think its the ecu but I want to be absolutely sure before I personally drop the money...

Reason being I had another vehicle that was doing the same thing...It was a dodge minivan of a customers...NO codes but it ran like crap at idle but at higher rpms it was ok...everything tested out ok per the FSM but on a hunch I swapped out the ECM and solved the problem

 

[baja1]

since an engine swap i've been dealing with a no spark issue, I too am seeing voltage at the IGF and should have a new ICM in my hand in the next couple of days. if this doesn't do the trick.....what the heck does a new ECM cost and is it simple to replace??

 

[jti30666]

costs for an ecm are anywhere from $600 - free....depending on who you know...

I'm not sure on these if they require programming but most likely will...

 

[jti30666]

interesting...after reading another post online where the OP accidently dropped the ICM/ignitor I went outside and tapped on the ICM while the runner was running and it ran perfectly at the suspected rpms but then started to run like pure Sh**...now I'm getting a solid misfire on cyl 1 & 4....

 

[baja1]

interesting...after reading another post online where the OP accidently dropped the ICM/ignitor I went outside and tapped on the ICM while the runner was running and it ran perfectly at the suspected rpms but then started to run like pure Sh**...now I'm getting a solid misfire on cyl 1 & 4....

whats your next step? I have a new one in hand, praying it is the culprit. I have 12vdc at the coil to ground, not at the coil connector??? I think I remember reading the ICM switches ground not pos. voltage???

 

[jti30666]

correct on the ground trigger...positive side produces voltage to the "field" coil....when grounded from the ICM it triggers the coil to "fire"...from view the sheets it does appear that power is supplied to the coils from the icm as well...let us know what happened

 

[baja1]

ay carrumba! installed the new ICM and now have spark! plugs have gasoline on them.....won't start, doesn't even try :Cry:
I tried spraying starting fluid thru the TB, nothing. does that starting fluid actually make its way thru the plenum down to the intake manifold?

 

[Marvfromnewyork]

Wait...

Omg this post isn't that old So I hope someone could reply but everything you have described in your initial post is exactly what I am going through right now with my 2000 4runner. Started happen a while before it stopped working it would just stagger while I am trying to accelerate. I thought it Was just maybe bad gas. But then one day it just wouldn't start at all it would just keep turnin over and turning over and no start. But then the next day it would start and one perfectly lake I just dream to what happened the day before. And eventually it wouldn't start at all finally got a check engine light which said Crankshaft sensor. Replace. still nothing so I went ahead and replace the Cam shaft sensor still nothing finally after trying got a nother check engine light that says miss fire Ignition coil #1, So I went ahead and do a full tune Up. replaced fuel filter Ignition coil 1.plug wires set. all plugs and fuel injector...... still nothing.... please help