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The last line I typed on my last post:

Fast Frank said:
Somebody needs to hook that baby up to a real diagnostic scanner and look at what's going on when it's in the no start condition.
There's a reason why throwing parts at the truck is a bad idea.

By now, you should be well aware of what that reason is. It cost a shit load of money, and it might not fix the truck.

So, stop doing it already! It's dumb!

Call somebody that's supposed to be a reputable repair shop.

Ask them "Do you have a real scanner that lets you see the inputs to my computer while the motor is running?".

If they say no, hang up and try somebody else. Somebody, somewhere, in your town has the right equipment to correctly diagnose your situation.

When this person hooks up to your truck, and duplicates your no start situation, he's going to scroll through the data and say "Here it is".

Then, he's going to tell you why it won't start. After that, you can fix it.

It will probably cost a hundred bucks, and by now you should realize that it's fucking cheap compared to throwing parts at it.

GO GET IT DIAGNOSED!
 

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Frank is of course, right. But to add to my posting with the refurb'd MAF's...

22250-75010

is the part number. On a few diff directory listings, this # is the correct part for your 97 2.7/4cyl. 4runner/Tacoma run the same engine components those years (to the best of my knowledge/research abilities)

I would Call SIA and make sure you're ordering the correct part - Count pins on the harness of your MAF, look for part numbers on your existing unit.

So Here's how i'd swing the diag if it were me:

1) Back up a couple of months to before you threw a bunch of money at it willy-nilly ;) - (sorry, i had too!)
2) Grab 7$ bottle of MAF cleaner (the stuff i linked too, which is... safe for MAF's)
3) Clean the shit out of the entire intake tract and throttle body, including the MAF. Get yourself a new air filter (non-oiled, non-FRAM)
4) Did it fix problem?
4a) Yes! drive it around town for a few thousand miles.
4b) Did the problem come back?
4c) Yes! Follow Franks advice. Which may mean replacing with a refurb'd MAF
5) No! Follow Franks advice.
6) Get your truck running happy by replacing the correct parts and go enjoy the High Sierras! :D
 

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whatever you do do not touch the wires in the MAF at all, just hose them down with the cleaner. if you touch them with the plastic hose thingey on the MAF can or with your fingers you will be buying a new MAF.

i hosed mine down with that stuff and it worked perfectly. just have to be careful that nothing touches the wires in there.
 

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Discussion Starter · #24 ·
I understand what Frank said. This has been going on for several years now, and its been to four different shops.

No error codes unless you can replicate the problem, and replicating the problem is tricky. You have to time it just right. You also have to go out and drive it on a hot day. It will not happen if you just run it on the dyno. Then if you just cut it off, it starts right back up. You have to time it for the heat to soak in, but get at it before it cools off. Usually will not happen if you park it in the shop in the shade. You have to do it out on the hot parking lot. Its hard to do when its a daily driver. I bought a new car a few months ago, and now I have more options

I admit I threw parts at it out of sheer frustration. But I have big long term plans for the truck, if I can just get past this. Some of the stuff, like radiator and injectors, I would have done anyway.
 

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Discussion Starter · #25 ·
My mechanic tested the MAF with pressurized air, and says it reads just fine. It is convenient. His shop is directly across the street from my office

He cleaned it anyway, so see if that helps.

I have a special test. My comute is 15 miles, mostly freeway, so drive home and wait 10 minutes and try it.

At least I have a way to get it started when I stranded...
 

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Discussion Starter · #27 ·
I think I was wrong about the MAF. After talking to Toyota tech it seems the one for the 2.4 and the 2.7 are different. They did change both after the first couple years. That might indicate there was a problem with it, or maybe they changed something else about the fuel system that required them to change the MAF. The "Something Else" might be the problem.

Cleaned and tested the MAF with pressurized air. It seems to be working....

But still have the problem. Now very discouraged again.

Everything seems to be working. Replaced every damn thing I can think of. I suspect some problem between the air temp sensor, the MAF and the ECU, but already replaced the ECU. Not willing to just throw another really expensive part at it.

Back to what Frank said. Mechanics have the equipment to do a diag, but its hard to get them to go to the trouble of replicating the problem to do the diag. Mechanics do not get so emotionally involved, and most just do not see thee sense in putting so much money into a truck with no blue book left to it.

At least I know how to get it started so I do not get stranded. The CEL light comes on, and stays on, once the air temp sensor is pulled, but mechanic can clear it to get it smoged.

But I do not think I want to put like $10K into the rebuild I want to do, unless I can really get this fixed.

I do not think I am that crazy for wanting to do this. My 2WD regular cab Tacoma only weighs 2,560#. The 2RZ motor has 143Hp and 160# of torque. There is no truck on the market today with that kind of hp/torque/weight ratio or build quality.
 

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Discussion Starter · #29 ·
Besides the new ECU and harness, would need a new MAF match. That would be damn near as much as rebuilt motor

Got to admit to at least looking at used ones in the 2003-4 range
 

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parts that I threw at it:
Radiator
Fuel pump
Fuel Pressure Regulator
Crankstaff Postion Sensor
Ignitor Module
ECU
Fuel Relay witch
Distributor Coil
Heat Shield
Distributor
Air temp Sensor
Throttle Body Sensor
Injectors
Coolant Sensor
have U replaced the fuel filter ?
 

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I have a 2000 v6 sr5, and I sortof had the same problem, only mine idles rough at idle-really low then dies. This happens after its good and warmed up. I also have a K&N filter installed. After reading several threads not only from this form but from others, I found alot of people had problems with carbon biuld-up on the AIC -air idle control. $200.00 part. I cleaned this the best I could with throttle body cleaner and brush and reinstalled it., also sprayed off my mass air senser with mass air senser cleaner, at this point you have to disconnect your battery to reset the limp mode the computer is in-all sensers were ok readings on ohm tester before I did this- This combo seems to have fixed my problems--Good luck
 

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Discussion Starter · #32 ·
I think I did early on, and did not mention it, but I will have it replaced next time I drive it to be sure
 

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I have a 98 2.7 with the exact same problem and have come across many many threads regarding this issue. Thing is, my injectors aren't firing when it's acting up. I tested them with a noid light and am getting nothing. No one else has mentioned this symptom. Wondering if anyone else has checked or not. I will try and start without IAT sensor, but it is incorporated into the MAF on my year. I will try disconnecting MAF harness and use jumper leads to connect the needed terminals while leaving the IAT terminals open and see if it remedies mine as well. Just wondering if anyone else's injectors are dead during crank/no start issue. Heard that the injector drivers on ECM may be wearing out. Hmmm?
 

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Thing is, my injectors aren't firing when it's acting up.
Now there's something you can work with.

Question- Are the spark plugs firing when the injectors are not?

And is the check engine light on?

Most likely you have a code to work with. Have you pulled trouble codes?
 

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Have you guys with this problem checked your EFI relay? I can imagine a heat soaked relay not working, but it would work at normal temp.
 

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How I solved my problem

I have a '96 4runner with the 2.7L 4-banger. (original owner)
It had the exact symptom of the original post on this thread: After driving on a hot day it would crank easily but not restart...waiting 15 minutes it would start right up.
Ultimately I discovered 2 issues...
1. My fuel pressure regulator didn't hold fuel pressure on shut off. I discovered this by buying the Auto-Meter part #2276 Banjo bolt that I could hook a fuel pressure gauge to. I enlarged the hole in the banjo bolt to match the hole size in the Toyota original one...as after my final fix, I left the Auto-Meter part in and capped the hole. The FSM said the rail was supposed to have >21psi after 5 min...with the old regulator the pressure dropped to ~12psi in a minute. The new regulator still had over 40psi after 5 min. I hoped this would be "the fix" but, it did not change the behavior even though it needed to be replaced.

2. My MAF was not working correctly because the resistance elements had a lot of accumulated dust caked on the wires. This was much more frustrating to determine as I tried a bunch of other things before discovering the dust on the MAF. (replaced the intake air sensor...because with the OBD we could see that it was reading ~35C when the air should have been ~25C...but the replacement read 35C too. Replaced the ECT (Engine Coolant Temperature)...this was because we were not figuring it out and my friend (car mechanic) suggested we change it as he has seen strange things when the ECT was not working correctly...replaced the upstream O2 sensor because the car was failing smog at the same time...replaced plugs, rotor and distributor cap...they needed to be replaced anyways...replaced the coil...still with all that, the car would not restart on hot days.

I bought the MAF cleaner in a can...cleaned the wires (without touching them) and the issue is fixed.

I hope this helps with some of you trying to troubleshoot your "no restart when hot" issue.
 

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same issue 1999tacoma actually sollved

I had this same exact issue and as of today (8 mechanics and thousands of dollars later) the problem is finally solved. I brought my truck to a former porsche technician and right away he suggested that it was probably the coolant temp sensor that wasnt reading properly, thus causing me much grief when trying to start the engine hot. Previously other mechanics replaced the crank position sensor, the throttle sensor, all the wiring, fuel filter, fuel pump (cleaned out the fuel lines too) plugs, battery etc.... None of that helped at all. After replacing the coolant temp sensor, shes been starting fine every time. Fuuuuuuuckkkkkkkk yeahhhhh
 

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I had this same exact issue and as of today (8 mechanics and thousands of dollars later) the problem is finally solved. I brought my truck to a former porsche technician and right away he suggested that it was probably the coolant temp sensor that wasnt reading properly, thus causing me much grief when trying to start the engine hot. Previously other mechanics replaced the crank position sensor, the throttle sensor, all the wiring, fuel filter, fuel pump (cleaned out the fuel lines too) plugs, battery etc.... None of that helped at all. After replacing the coolant temp sensor, shes been starting fine every time. Fuuuuuuuckkkkkkkk yeahhhhh
Thanks for the feedback!
 
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