Hello everyone, I’m reaching out to this community as I’ve hit a wall trying to solve a perplexing issue with my 1996 4runner. I’m hoping someone here might have some insights or suggestions that can help me get my trusty Toyota back on the road. I’ve been active on Toyota-4runner.org forums, but the problem seems to be stumping even the experts there. I’m turning to a broader audience, inspired by Scanner Danner’s videos, hoping fresh perspectives can shed light on this.
Vehicle Background: My 1996 Toyota 4Runner SR5
Let me give you some background on my vehicle. It’s a 1996 Toyota 4Runner SR5 2WD with an automatic transmission. Under the hood is the robust 3.4L V6 engine, the 5VZ-FE model, with approximately 155,000 miles. This engine configuration utilizes a waste spark ignition system. It features three ignition coil packs positioned on the passenger side cylinders, with the waste sparks occurring on the driver’s side. These coil packs are integrated with an Igniter module, which is crucial for communication with the Engine Computer (ECU). The igniter sends the vital Ignition Confirmation Signal (IGF) to the ECU. This IGF signal is proving to be central to my current problem.
Harsh Environment: Island Life and a 1996 4Runner
My 1996 4Runner and I are currently located on an island in the Eastern Caribbean while I attend graduate school. The island’s environment presents some unique challenges. We frequently drive on unpaved dirt and gravel roads, endure severe hurricane-force storms, and experience intense UV exposure along with corrosive salty sea air. This vehicle has been passed down through students over the years, and it’s fair to say that not all previous owners have been equally diligent in its upkeep.
The “Dying at Idle” Symptom and the P1300 Code
The trouble began with what I’ve been calling “dying at idle.” One day, while checking the transmission fluid in a parking lot, the engine simply shut off. There was no rough idling or sputtering—it just stopped. It restarted without issue, but the Check Engine Light (CEL) illuminated. I didn’t have an OBDII scanner immediately available, so I ordered one online and continued driving in the meantime. The “dying at idle” issue became more frequent, occurring at stops and even while waiting in line. Eventually, it got so bad that the 1996 4Runner would stall even when backing out of the driveway. I had to park it and wait for the scanner to arrive.
Upon receiving the scanner, I immediately checked for error codes. The scanner revealed a P1300 code. My research indicated that for Toyota vehicles of this era, particularly the 1996 4Runner, the P1300 code signifies an “Igniter Malfunction Bank #1.” Interestingly, I wasn’t experiencing any noticeable misfires or excessively rough idling, and there were no other codes indicating spark-related issues. Initially, the “Bank #1” designation confused me, leading me to suspect ignition coil #1, which controls cylinders 1 and 4. The code clearly pointed towards the igniter module as a potential source of the problem. However, a new igniter module is a significant expense. Before committing to that, I decided to investigate further. I compiled a list of potential causes for the P1300 code:
- Igniter Module
- Ignition Coils
- Crankshaft Position Sensor
- ECU (Engine Computer)
- Spark Plugs
- Misfiring
- Shorts in the Wiring Harness
Troubleshooting Steps and Parts Replaced on the 1996 4Runner
To systematically diagnose the issue with my 1996 4Runner, I consulted the Factory Service Manual. Using a borrowed multimeter, I performed several tests, following the troubleshooting procedures outlined in the manual. The components I tested and their results are as follows:
- Camshaft Position Sensor: Within normal specifications.
- Ignition Coils (3):
- Primary Resistance: Normal.
- Secondary Resistance: Normal.
- Wiring Harness Continuity: Checked between the Igniter and ECU, and between the Igniter and coil packs – continuity was confirmed.
- Voltage at Igniter: Verified as proper.
- Voltage at IGF Pin on ECU: Verified as proper.
Prior to this issue arising, I had already ordered some maintenance parts. In an effort to resolve the problem, I proceeded to install these new components on my 1996 4Runner:
- 6 new OEM spark plugs
- A set of new NGK low resistance ignition wires
Even though the ignition coils tested within factory specifications, a suggestion was made to replace them. I invested in three new Denso ignition coils and installed them. The engine does run very smoothly when it is running.
While inspecting the wiring, I noticed a wire on the igniter that appeared different and slightly loose. Upon closer examination, I discovered a splice point within the wiring harness. To ensure a solid connection, I soldered the wire directly to the igniter connector and resoldered the splice wires, verifying low resistance afterward.
Considering the P1300 code’s indication of an igniter malfunction, I eventually sourced a used igniter module from eBay at a reasonable price and replaced the original one in my 1996 4Runner.
Unfortunately, none of these parts replacements made any difference. The 1996 4Runner still starts easily and runs smoothly, but only for a short period—typically 10 to 15 seconds, sometimes up to 30 seconds. Then, it stalls and throws the P1300 code again, regardless of how many times I clear it. According to the Factory Service Manual, the P1300 code is triggered when the ECU does not receive the ignition confirmation signal (IGF) after a set number of engine cycles. Without this IGF signal, the ECU cuts off the fuel supply, causing the engine to stall. The FSM directs me to check the IGT signal coming from the ECU while cranking the engine. I haven’t been able to perform this test yet as it requires a second person to assist. However, I recently acquired my own multimeter, so borrowing is no longer necessary.
The Mysterious Condenser
Recently, I discovered a component I hadn’t seen before, taped to the air intake tube, out of sight. Toyota refers to it as a condenser—essentially a capacitor, apparently acting as a noise filter. I’m uncertain if it’s related to my current problem with the 1996 4Runner, but I tested it with a multimeter and got infinite resistance, suggesting it might be faulty. Fortunately, it’s relatively inexpensive, and I have ordered a replacement.
I’m open to any suggestions or insights you might have. Could this condenser be related? What other steps should I take to diagnose this P1300 code and get my 1996 4Runner running reliably again?
Thanks in advance for your help,
-Z
