My 91 Camry (4 cyl) has had an intermittent problem. Very occasionally it fails to start, or stops shortly after starting. At this point there is no spark. In most cases the spark returns within 30 min, but on one occasion I had the car towed to a mechanic, but when it got there it started, and he wasn't able to diagnose the problem. I joined the AA (NZ's AutoClub) to get free towing if needed, and the car has behaved itself since then - until a week ago, when it failed to start when we were about an hour from home. I called the AA, and the guy who came made some electrical measurements, checked fuses etc., then brought a hammer from his truck. As I turned the engine over, he hit the distributor, and the car started. Interesting. While waiting for the AA I pulled the error code, #43.

A couple of days ago the car failed to start at home, over a period of a couple of days, and I decided to try to trouble-shoot it. Following the instructions in my manual, I went through the ignition checks, all OK, until I got to the check for the pickup coil. Here you should measure 140-180 ohms between terminals G and G-, and G and NE. I'm seeing open circuit, although interestingly the meter shows a very brief flash of a finite resistance value, i.e. a number of the order of 100. Unless someone tells me otherwise, I assume my pickup coil has a fault in the circuit, presumably a break.

According to the manual, the solution is to replace the distributor. Is this really necessary? Why not just replace the pickup? Is it not removeable?

I'm wondering about the error code. I see that 43 is Starter Circuit Signal, which doesn't really seem consistent with my symptoms.

Any suggestions?

Thanks
Gib

 

Correction and update: I was misusing my digital ohmmeter. I now see that the pickup coil resistance is 220 ohm (both ways), and this is confirmed by my analog meter. According to my Haynes book the resistance should be 140 - 180, but the book goes up to 1990, and my car is 1991 (made in Australia). 220 may be OK - how to find out?

According to the book, code 43, Starter signal, means No STA signal to ECU when vehicle stopped and engine running over 800 rpm. The Trouble areas are:

1. Main relay circuit
2. IG switch circuit (starter)
3. IG switch
4. ECU

(I should emphasise that the engine turns over fine, no spark).

Question: What indications will there be that there is a problem with the main relay circuit? When I turn the ignition on all the usual lights come on. Should I hear any relays switch? The main relay is, I believe, below the dash on the rhs of the driver compartment. I do not hear anything from there when I turn the ignition on.

 

If you can find the pickup, just replace that.

The resistance can increase if the engine (aka the sensor component) is hot. Any change in starting success if engine hot or cold?

Have you tried looking in the Autozone websites vehicle repair guide section for specific data on this year?

Sometimes the ign coil can cause problems and get worse if the air is moist.

For main relay would assume this means to check if 12V power is getting to the igniter and ign coil. Same for ign switch. If 12V is at these parts then ign and relay should be OK.

There may be a couple of small electrical capacitors inside the distributor. On rare occasions these can fail causing strange problems.

 

For the last week the car has failed to fire - it seems to be permanently kaput now.

The ignition coil looks perfectly OK. We are at the end of a long dry summer here.

Voltages everywhere look OK. Is there any way to test the igniter, besides swapping it out?

If the pickup is OK, coil OK, relays OK, igniter OK, that just leaves the ECU. By the way, where IS the ECU?

 

According to the Autozone website pickup resistance should be 205-255 ohm.

Coil primary 0.38-.046 ohm
Secondary 7.7 - 10.4K ohm

Air gap 0.008-0.016 inch

Thought Code 43 was the Starter Signal Circuit whose main purchase was to increase fuel flow at engine start up.

Might be a way to determine if the igniter is receiving power the ECU IGT and IGF circuits.

For later models the computer puts out 4.5 -5.5V at the computer to the IGF and 0.5-1.0V at the IGT terminal. These voltages are with igniter disconnected, ign switch on and voltages compared to ECU ground.

The ECU is typically located behind the passengers side glove box upper area.

 

Thanks a lot Joey. That implies that the pickup resistance is OK, and the pickup is probably OK.

I'll try to check the igniter voltages as you suggest.


The ECU is going to be hard to access. That location hints at a possible cause of the problem. In heavy rain sometimes water appears on the floor on the passenger side. It seems that the channel below the wipers may have rusted through. If water has been able to get on the ECU that wouldn't be good for it.

 

Hi Joey, I followed your suggestion and checked voltages at the igniter connector. I see 5 v on the IGF wire, which is OK, but interestingly only 10 mv on the IGT wire. If the operation of the 91 model is similar to the later one, this could be a useful clue.

One thing puzzles me about the Haynes manual circuit diagram. It shows 5 color-coded wires connected to the igniter, but also shows two wires (with no color indicated) going from the igniter to the pickup coil in the distributor. I have a 5-way connector, with colors that align with the diagram, but no sign of the pickup coil wires. Is the manual just wrong, or has something changed from 1990 (the end year for the manual I have) to 1991?

I've searched online for a 91 or later circuit diagram, no luck.

If the IGT voltage level really is wrong, does this suggest that the ECU is at fault?

 

Joey, I believe I've cracked it! I finally (should have done it long ago) opened up the left-side dashboard to check out the electrics under there. I immediately saw big chunks of rusty steel that had fallen down among the wiring. The ECU is thankfully well away from this area, but seeing rust on a relay casing I decided to check all the connector contacts. I quickly found evidence of corrosion on many contacts. I cleaned them up as best I could by scraping and rubbing with wet and dry (can't get into the female connectors), put it all back together and the car started. Whew!

Unfortunately the place where the body has rusted through (in the channel under the windscreen wiper) is really inaccessible - it's all welded up. The best I've been able to come up with is to squirt urethane foam in from the opening, aiming the foam off to the left side. Of course this interfered with the wiper lever operation, so I had to free that up by removing some foam. I think what I have is not completely watertight, but it should certainly reduce the water intrusion. By the way this seems to be a design flaw (or assembly flaw), since the channel has rusted through in the same place on both sides. I think what happens is leaves fall into the channel and block the exit hole, which has rubber flaps on it. I know this because on the other side I removed the front wheel well panel, and tried to do a more thorough repair, but I still confronted the problem of getting access to the inside of the channel.

Anyway, I feel pretty confident that I've located the cause of the spark failure, and I can improvise some way to shield the left connector-relay block from any water that does get in.

Thanks for your help.
Gib

 

If you have not figured it out, i had this problem with mine and it turned out even though i thought the ignition coil was ok there was actually a thin crack on the bottom of it (only found it by actually taking the coil out of the distributor and inspecting it)

another thing is there is a ground wire coming off the wiring harness on the passengers side just above the #1 cylinder injector if this wire comes loose then you will lose spark completely

i forgot to tighten the bolt one time and my car was dying every now and then and i thought it was a short in the main fuses because when i wiggled them it would start.

hope you figure it out if you have not already

Benji

 

Hi NovaMobile,

I'm quite doubtful about the coil being the problem. The car runs fine for weeks, then suddenly there's no spark. Then there is spark again. The error code 43 has no connection to the coil. Finally, the whole distributor + coil was replaced, without curing the problem.

The idea of a bad contact somewhere seems likely. This could be a ground wire, a connector, or even a bad conductor. It has to be something that doesn't affect the supply of current to the distributor, though, since in the failure mode (no spark) the voltages measure OK. I know that the error code is not conclusive, but surely it provides a clue. The car is running at the moment, but I have no confidence that the problem has gone.

Cheers
Gib