1989 V6 3.0L Toy Pickup Intermittently Dies

ignition
stalling
toyota
start
tacoma
gasoline

#1

I have driven small Toyota 4X4 pickups since 1980 including an '89 for the past 25 years and > 200,000 miles. One day a couple of months ago it would crank but would not start although battery and starter seem fine. I did some basic testing eventually measuring the ignition coil resistance (within published range) and inspecting the distributor cap (looked fine). Upon reassembly, it started right up and ran fine for a few weeks. I hadn’t really done anything beside cleaning the rotor and cap contacts, moving around the wiring while in the process.

A few weeks ago I was driving in traffic just a few miles from home and it momentarily lost power twice within a mile. Check engine light was noted the second time. I was busy watching the cars ahead of me the first time. Both times it resumed running on it’s own and I continued on. A couple of weeks later it died three times within a few miles from home.

The first two times I was able to pull off out of traffic. Several minutes later, I was able to restart the engine. The third time I was stuck in a turn lane at an intersection, police arrived right away and the vehicle was towed to the dealer where I had purchased it only two miles away. They have been unable to reproduce the problem but believe they have eliminated the fuel filter and fuel pump as the cause. They have driven the vehicle several miles and left it running for an hour and a half with no problems noted. No diagnostic codes were recovered.

They now want me to retrieve the undiagnosed, unrepaired vehicle. We know it will fail again, probably under the worst possible circumstances. In heavy traffic, a multi-vehicle crash with associated injuries or deaths could result. It’s like if the vehicle itself doesn’t tell them what to do, they don’t know how to approach such a problem on their own any more. I’m not in a position to pour unlimited funds into a vehicle I have recently replaced (with a 2014 Tacoma). There must be a logical approach beyond checking the fuel filter and pump but they seem clueless. I can’t safely drive the vehicle and won’t offer it for sale until the problem is identified and corrected.

Educated advice would be much appreciated!


#2

The stalling might be caused by a faulty ignition control module/igniter.

https://www.rockauto.com/en/moreinfo.php?pk=49991&cc=1277704&jsn=342

This can easily be determined by starting the engine, and then take a heat gun and point it at the ICM/igniter.

If the engine suddenly stalls out, that’s the problem.

Tester


#3

I own a similar vehicle, early 90’s Corolla with over 200K. Similar designs, but probably different engines. Mine is a 4afe engine. I agree w/Tester above, it sounds like the ignition module is going bezerk when it gets hot. The next most likely would a crank or cam sensor heat-related failure.

There must be a logical approach beyond checking the fuel filter and pump but they seem clueless

Yes there is. The first thing is to read out the diagnostic codes from the engine computer memory. That may provide exactly the information needed to nail down what’s failing. If not, then the shop should determine if the intermittent failure is due to spark or fuel. If I had that problem on my Corolla, and I couldn’t get it to happen using the heat gun idea above, or just waiting for a hot day and idling the car or driving it around the block until it failed, then I’d bring the required diagnostic equipment in the trunk to make that determination with me as I drove the car normally about town.

If you aren’t qualified to do that, one idea is to allow one of the shop techs to keep the car and drive it as their daily driver. The can load it up with the proper diagnostic equipment in the trunk, then when it fails, they can quickly determine if the problem is spark or fuel. Best of luck.


#4

I agree that igniters and modules fail and thank Tester for the diagnosis trick. Knowing how to test things can speed the diagnosis.


#5

Some heat guns will quickly destroy the module so be careful…Is this vehicle carbureted or fuel injected?


#6

Concur w/ @Caddyman , using a hair dryer is probably better than a heat gun. At least the kind of heat guns you’d use to remove paint. When I was testing my truck’s carburetor choke bimetalic spring, making sure it rotates with temperature, I used a hair dryer and indeed it spun in a circle as it got plenty hot, no need for anything hotter than a hair dryer.

There’s another trick I’ve used to test heat sensitive components, you folks might want to keep it up your sleeve as a back-up. Electronics supply stores sell a product – I use one made by CRC – which is sort of a freezer in a spray can. Spray it on a electrical component and it gets really cold, like -60 degrees F, & fast. Sometimes that will quickly isolate which component is heat-failing intermittently.