Engine saga continues

B

billsheila

New member
I had another post (my introductory post, not titled well), so I thought I would update and see if any more suggestions out there.

Symptom: deep hesitation, popping noise, no power. Only seems to happen when engine is warm, and upon restart after sitting for a bit. No codes, except as noted below.

Stuff done in search of repair (some thankfully by the prior, recent owner):
1) new O2 sensors
2) new fuel pump
3) new MAF sensor
4) Throttle body cleaned, both sides, plus cleaned out Idle Air Control Valve
5) swapped out main computer (bought one at salvage yard), no change...now trying to return computer
6) Throttle position sensor changed

Performed tests on IAC valve, seems to work as advertised at least relative to A/C use etc.

In prior post people suggested injectors, and Toyota repair database suggests maybe temp sensor. Any other thoughts on where to go next (the dealer is starting to sound like a possibility!) Are injectors easy to test?

Many thanks.
 
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Newer to do plugs and wires. Injectors r simple to test, need test test light kit from any parts store.
 
Original Post.

I assume this was the original post. If not just let me know and I'll correct it.

Inspect the plugs and replace if they are not NGK or Denso brand dual electrodes. Inspect the plug wires with a bright flash light and look for any signs of cracking or kinks. You may want to just replace them altogether if they are old or if you do not have service records of them being replaced. The hesitation and power loss is typically caused by something in the stroke cycle not completing and spark is the simplest in the cycle to check.

If the fuel filter hasn't been changed then you should swap that out as well. I would hope that someone would not install a new fuel pump without changing the filter, but you never know. Fuel delivery is the logical next step in power loss and hesitation issues. It sounds like air delivery is well covered with the new MAF sensor and a clean throttle body and IAC.

I would recommend you disregard the P0171 for now since you mentioned there is no code present. It sounds like you have a misfire condition which doesn't always generate a code immediately, especially when it seems to clear up on it's own. A diagnostic scanner will display live data and would be really helpful if none of the above correct the problem.
 
Link to original post correct, thanks for doing that. And yes I forgot to note that the only code ever thrown in this whole affair was P0171, but as you say this could be misleading.

Yes, FF was changed when pump was changed.

I wondered about ignition so perhaps that is next, it seems to break through whatever trouble it is having and then runs fine at higher RPM, ie above about 1800 to 2000. Just a thought, any chance it could be one of those ignition units (not sure what they are called) that sits on top of the passenger side plugs....or do these just work or not work? Regardless, plugs and wires are easy enough and with 110K probably good time to change them anyway. The wires look stock, but it is hard to know. While I am in there doing that I guess I could do the electrical tests on the injectors.

Appreciate the suggestions. I notice none said "go to the stealer"!! :bluejump:
 
billsheila said:
Link to original post correct, thanks for doing that. And yes I forgot to note that the only code ever thrown in this whole affair was P0171, but as you say this could be misleading.

Yes, FF was changed when pump was changed.

I wondered about ignition so perhaps that is next, it seems to break through whatever trouble it is having and then runs fine at higher RPM, ie above about 1800 to 2000. Just a thought, any chance it could be one of those ignition units (not sure what they are called) that sits on top of the passenger side plugs....or do these just work or not work? Regardless, plugs and wires are easy enough and with 110K probably good time to change them anyway. The wires look stock, but it is hard to know. While I am in there doing that I guess I could do the electrical tests on the injectors.

Appreciate the suggestions. I notice none said "go to the stealer"!! :bluejump:
Click to expand...

The ignition unit you're talking about is called a coil pack. They can definitely go bad and would essentially have the same symptoms as a bad plug or wire. Good luck with the hunt! :hunter:
 
If you look on the plug wires, and they are OEM style, they are stamped with the year. That could give you an indication of how old they are.
 
In your original thread you never said you cleaned your IAC. You said your mechanic told you to put on the A/C and he determined that it was fine. I'm no expert on the workings of the IAC but I've never heard anyone say if turning on the A/C bumps up the RPM's then it's fine. You may still need to clean it.
 
I cleaned the IAC by spraying throttle body cleaner down the hole in the throttle body that leads to the IAC...the liquid came out a pipe on the bottom of the IAC.

I just changed the engine temp sensor. No change.

Then I changed plugs to double electrode platinum and new Bosch wires. Seems worse. In fact I now think I may be onto something with the ignition. It seems now like it is only running on 4 cylinders all the time, no power at all. This leads me to wonder if I might have a bad coil pack...perhaps it was intermittent with the old (copper) plugs but just isn't cutting it with the Platinums. Should I try to go buy one coil pack and try it in each spot maybe?

This is turning into quite the project. Please let me know about the IAC as while I am in there if there is more to do to clean it I can do that as well.

Pretty soon I will have a new truck!!
 
I've never heard anything good about Bosch ignition parts on Toyotas.......always bad... I'd put the old wires back on if you still have them.
Are you using the FSM for testing?
 
Still have old wires but clips were brittle on the coil packs, so if I change them back I would need new clips or go to new parts at the dealer. One other point that may be of interest. Autozone reported to me that the stock plugs were just copper, suggested that maybe coil packs were not designed for platinum, so I changed out the new platinum plugs while playing with the new (from Autozone) coil pack I bought. Couple of things learned:

1) coil packs are all OK. It ran about the same regardless of which coil pack was pulled and replaced with the new one.

2) It was running on only 5 cylinders because I hadn't pushed one of the caps down far enough. This smoothed things out obviously, but the main symptom of hesitation remains. It does run smoother on the copper plugs, so I went with those.

Any advice on the idle air control valve? Did the way I cleaned it suffice (ie blow cleaner in from the top of the throttle body and let it drain out the tube on the bottom. Does this do it...or do I need to take the whole thing off (including coolant lines) and go at it on the bench?

Thanks!!
 
And then there were three...

OK. I know this is getting boring. But my truck is still not healthy. Re my bad choice of wires (Bosch) I am sticking with them for now because the root issue is still happening!!!!! WTF, I say. :wtf::wtf::wtf: I spent the whole day on the ignition system and the coolant temp sensor. Despite the poor Bosch choice (all Autozone had available), when it is isn't hesistating, it purrs just fine with the Bosch stuff.

To recap:
The problem only occurs when the car is warm and has been sitting for a while (for example like 10 minutes). If it sits longer or shorter or is stone cold, it seems OK. The issue (best described as dead acceleration, popping, farting, no power)...only occurs once. After I break through it this first time it occurs, it will seldom repeat on that run.

Replaced or checked:
Main ECU (salvage unit installed, problem persisted)
MAF (new)
plug wires (new)
plugs (new)
coils (new unit tried in all 3 locations, no change)
coolant temp sensor (new)
TPS (new)
Both O2 Sensors (new)
Throttle body cleaned
Air induction system checked for leaks (new air filter etc)
All hoses checked for cracks, leaks etc
Idle Air Valve Cleaned (as described in prior post).

Early on I had CEL (P0171) but this has not re-occured. Checked the system for other codes (not my tool, borrowed from AZ) no codes stored.

Now on to the remaining three (unless I am missing something):
1) Crank Position Sensor
2) Injectors
3) Cam Position Sensor

I don't have the tools to properly check the injectors, so what is the recommendation on this...dealer? Only other idea I can think of is to buy one injector unit and then install it in one hole at a time and try it each time. Taking the intake off to get at driver's side injectors won't be fun!!

Each of the CPS and CamPS are like $85 or so. One person advised they have seen these sensors be "temperature sensitive".

My personal theory is that I have a bad (leaky) injector (or perhaps more than one?). When it is warm and sits for a short period of time fuel leaks down based on residual fuel pressure...then it chokes on this fuel. After that doesn't repeat until the next leak down.

Any suggestions at all on "the remaining three" and any advice on how best to pursue my injectors theory would be appreciated.

Thanks
Bill
 
I think if you take it to the dealership....the first thing they are going to want to do is replace the Bosch wires and non OEM plugs.

How much time and money have you thrown at this problem now?

Personally I think you went off the road when you starting replacing probably good OEM electrical equipment with aftermarket junk.

IMO, it's time to seek a professionals help.

If you would like to carry on though....there are tests in the FSM for the crank, cam and I posted the injector test above.
 
notrayray said:
I think if you take it to the dealership....the first thing they are going to want to do is replace the Bosch wires and non OEM plugs.

How much time and money have you thrown at this problem now?

Personally I think you went off the road when you starting replacing probably good OEM electrical equipment with aftermarket junk.

IMO, it's time to seek a professionals help.

If you would like to carry on though....there are tests in the FSM for the crank, cam and I posted the injector test above.
Click to expand...

ANSWER:
Lots of time, not so much money. The truck is new to me and the prior owner spent a bunch on it chasing the same problem, all in the last month. He had all the work done at a shop, I have been doing it myself. Oh I forgot one item on the list above...the worst of his expense was a new fuel pump and filter.

I hear your love for OEM parts loud and clear, but given they are about 1.5 to twice the cost of the Autozone variety, I choose the latter...perhaps to my peril but I have to think that many other people have their vehicles operating with these parts just fine, or AZ would soon be out of business.
 
billsheila said:
ANSWER:
Lots of time, not so much money. The truck is new to me and the prior owner spent a bunch on it chasing the same problem, all in the last month. He had all the work done at a shop, I have been doing it myself. Oh I forgot one item on the list above...the worst of his expense was a new fuel pump and filter.

I hear your love for OEM parts loud and clear, but given they are about 1.5 to twice the cost of the Autozone variety, I choose the latter...perhaps to my peril but I have to think that many other people have their vehicles operating with these parts just fine, or AZ would soon be out of business.
Click to expand...

It seems it's mostly Toyotas that are picky about what ignition parts you put on them......
The link in my sig has OEM parts resources online for a discount. (there are more than what is listed in my link, but these are the ones that I have used.)
 
You can follow the diagnostic procedures listed in the FSM to chase down your problem instead of throwing parts at it. Most of the diagnostics can be done with hand tools and a multimeter too. I would strongly recommend running only Denso or NGK plugs and wires though. Bosch is just going to be another problem for you to deal with. I had to learn that the hard way :cheers:
 
UPDATE Re ENGINE ISSUE

Well I may have stopped having to do the following: :redbrick:

It appears my entire issue may have been caused by malfunction of the "Code Alarm" remote starter and alarm system that was in the truck when I bought it. This unit had malfunctioned at some point so the siren was disconnected, but left hooked up for purposes of at least having the key fobs work the door locks. Well it is also hooked up to the ignitor. Removed the whole mess and so far the problem has not returned.

UPDATE AGAIN: SPOKE TOO SOON. I JUST WENT OUT FOR A QUICK "RUN" AND THE PROBLEM IS BACK. THIS IS SO ANNOYING. BTW I DID SEEK PROFESSIONAL HELP AND DROPPED $400 ON THE ABOVE DIAGNOSIS. I GUESS NOW I TRY ANOTHER DEALER?
 
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Most smaller shops are going to charge around $70 an hour and many specialize in diagnostics. Dealerships specialize in $100 an hour rates and inconsistent results. I would let the service manager know that their diagnosis was incorrect and see if they will try to correct it at no charge.
 
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