[Gargravarr]

Okay, scratch the other two threads I made, one was redundant, the other, I've applied as much of what I learned as possible but I'm back at square one and need more help!

This time, Dragon cut out on the highway. I put an ignition tester on the spark plug and it didn't flash, so immediately assumed the same ignition problems as before. I think the igniter may well have been dying slowly since November, so I immediately started tracking down a replacement. I picked one up today (as part of a big batch of parts I sniped on eBay), but after swapping in the replacement part I still have no spark.

Symptoms:
-Had been seeing intermittent ignition problems after bringing the car out of the garage
-Engine cranks fine
-Replaced the battery
-Replaced the alternator belt, the old one was badly worn
-No spark at the coil - held the ignition cable to the suspension bolt and nothing
-Can't find the check connector so I have no idea if there's a code 14 recorded

I haven't yet put the multimeter on the distributor pickup coils, but last time I checked them, in November, they were within tolerance, as were all the HT leads.

What else can I check? Starting to wonder if there's a broken wire somewhere, perhaps between the ECU and the ignition system.

 

[StanS]

When you roubleshoot you should track down the malfunction as close to the source as possible before you blindly replace parts or "fix" wires. So, does the ecu put out a signal to the ignitor? If not then what signal to the ecu is missing or incorrect. There's the wiring drawing in the online TSRM and also repair flow drawings (in the EFI section iirc). Also, a very good source explaining the engine and control operation is the toy written technical articles describing the design objectives and operation of the engine at www.autoshp101.com. You should spend some time and familiarize yourself with the engine operation. You'll save yourself lots of time with other problems as they arise in the long run.

 

[Gargravarr]

When you roubleshoot you should track down the malfunction as close to the source as possible before you blindly replace parts or "fix" wires. So, does the ecu put out a signal to the ignitor? If not then what signal to the ecu is missing or incorrect. There's the wiring drawing in the online TSRM and also repair flow drawings (in the EFI section iirc). Also, a very good source explaining the engine and control operation is the toy written technical articles describing the design objectives and operation of the engine at www.autoshp101.com. You should spend some time and familiarize yourself with the engine operation. You'll save yourself lots of time with other problems as they arise in the long run.

Hi Stan,

You linked me those articles in the last thread I made; you're right, they are very informative and I used them heavily in my diagnostics. As such, I've built on what I learned in the last thread and wasn't 'blindly' replacing parts - I had good reason to suspect the igniter, since I went through all the diagnostic steps last November. I'm planning to get an analogue voltmeter, so I can put it between the IGt feed and the igniter to see if the trigger is being sent. I'm quite familiar with the 5M-GE and its control systems by now, but I'm reaching the limits of what the manuals can tell me, especially as they are written for USDM vehicles. UKDM ones have subtle differences.

 

[Gargravarr]

Another thing I've noticed is that the Check Engine light is being a little inconsistent - most of the time it comes on steady with the ignition switch ON, but there have been a couple of occasions where it's blinked and gone out. It also seems to go out after a failed start. Could this be related?

 

[msgsupra84]

Check for voltage come from M-REL from the ecu. Also check fuel delivery. Ign, the efi system, and the check engine light get their power from there. Check M-REL at ecu and check for voltage at the efi relay #1. I had the same problem, fuel and spark cut off and i noticed a non existent cel. But where exactly your problem lies is anyones guess.

 

[Tanya]

Agree with possible EFI relay/fuse. I had an issue with a previous car several years ago where the EFI kept getting super hot and would shut the car down, and wouldn't restart until it had cooled down. During this time, the check engine light would NOT come on when the key was on. Anytime this happens it generally leads to that EFI relay, or an IGN fuse or a dropped ground wire.

 

[Gargravarr]

Check for voltage come from M-REL from the ecu. Also check fuel delivery. Ign, the efi system, and the check engine light get their power from there. Check M-REL at ecu and check for voltage at the efi relay #1. I had the same problem, fuel and spark cut off and i noticed a non existent cel. But where exactly your problem lies is anyones guess.

Agree with possible EFI relay/fuse. I had an issue with a previous car several years ago where the EFI kept getting super hot and would shut the car down, and wouldn't restart until it had cooled down. During this time, the check engine light would NOT come on when the key was on. Anytime this happens it generally leads to that EFI relay, or an IGN fuse or a dropped ground wire.

Thanks for the hint, both of you - I'll test the EFI relay and the signal coming out of the ECU.

There is one small advantage to driving classic cars - just about every possible problem is known by now!

 

[msgsupra84]

I should say i still have this problem, since i never found the problem lol i temporally routed the wire going to the efi relay (red/yellow) to the main relay #2. Never gives me a problem, although i wouldn't recommend this, it makes me very uncomfortable.

Also try another relay, just to be sure. If you haven't already that is.

 

[Gargravarr]

Hmm, inconclusive. I took off the Main relay and tested it according to the TSRM - it read 70 Ohms between terminals 1 & 2 instead of 40-60, so it's just outside tolerance. I don't know if that means it's faulty, or whether that was due to it being a little cold last night.

And of course, I couldn't find the No. 2 Main Relay! For all their greatness, Toyota have an annoying habit of laying out the engine bay electrics differently between markets so they don't line up with the TSRM! I found a relay beside the washer bottle and tested that, but I have a feeling it's something to do with the wipers.

I didn't test the Circuit Opening Relay but the problem isn't fuel delivery. I'm gonna buy all three off a car being broken so I can test them - come to think of it, I might need to ask the guy where the No. 2 relay is!

 

[msgsupra84]

#2 is on the left fender, its square. So you do have fuel flow?

 

[Gargravarr]

#2 is on the left fender, its square. So you do have fuel flow?

Not in the UK models, I'm afraid. Almost wish Dragon was a US model so the technical manuals lined up :32:

 

[Gargravarr]

Right, still won't start after another assessment. This time:

-Battery voltage 12.5V
-Removed both the 'EFI' and 'MAIN' relays from the fusebox (page 85 of the EWD), switched the ignition ON and reinserted them, both clicked
-Tried jump-starting to see if more power would help, no joy
-Bridged the fuel pump connector, but couldn't hear the pump running. I'm not sure if I got the bridge wire into the connector though, it's dark

I've got a borrowed known-working igniter to try tomorrow.

 

[StanS]

Why are you checking the fuel pump? If it's working it doesn't guarantee that there's fuel to the cylinders. Remove a plug and crank the engine a few times. If you smell gas then you have fuel. No gas smell, no fuel. Do you have spark from igtnitor output wire to ground? If not did you check if a signal is coming from the ecu to the ignitor. Autoshop101 shows what type of signals are required. Have you followed the diagnostic flow drawings in the TSRM? Assuming that you don't have an oscilloscope you can make a signal detector with two resistors and a capacitor to check for signal polarity.

 

[Gargravarr]

Why are you checking the fuel pump? If it's working it doesn't guarantee that there's fuel to the cylinders. Remove a plug and crank the engine a few times. If you smell gas then you have fuel. No gas smell, no fuel. Do you have spark from igtnitor output wire to ground? If not did you check if a signal is coming from the ecu to the ignitor. Autoshop101 shows what type of signals are required. Have you followed the diagnostic flow drawings in the TSRM? Assuming that you don't have an oscilloscope you can make a signal detector with two resistors and a capacitor to check for signal polarity.

I checked for fuel because MSG asked. Removing the spark plugs and cranking the engine is asking for trouble, in my opinion - one spark in the engine bay and I could set the engine on fire. Much safer to sniff the tailpipe. I can't honestly say for sure if there's fuel going into the engine; the smell in the tailpipe is quite weak and suggests that only residual pressure remains in the fuel rail. I know the fuel supply and spark are not interdependent, but it's an observation I made. I'll have another crack at testing the fuel pump today.

If you read my first post, I noted that I don't have a spark at the coil. As I have said before, I have gone through the Autoshop manuals; yes, they are extremely informative and have helped me understand how the 5M-GE works, but my symptoms are not correctly lining up with my understanding. There are subtle differences in the UK models. Please excuse the tone of this paragraph; each time you have offered help to me in the past, it has been 'read the Autoshop manuals' and I have said repeatedly that I have done so.

I've gone through the flowchart in the TSRM this time and I'm no closer to an answer. I made a small discovery; there's a mistake in the Haynes manual test for the coil. It lists the secondary resistance in Ohms when it should be in kilo-Ohms - testing the secondary coil with my multimeter on the correct scale worked. I've tested two coils and they come out at 13kOhms - this is above tolerance, but the second one is known good. The primary coils also measure at around 0.9 Ohms, again slightly above tolerance.

The coil live wire measures 5kOhms which is within tolerance. There is power at the positive terminal on the coil. I put an analogue voltmeter on the control wires to the igniter. There is a steady 1V at the white wire, which I assume is the IGt, when the ignition is on, which falls to around 0.5V when cranking. I can't be 100% positive, but I'm not seeing any voltage at the pink wire, which I believe is the IGf. The wire colours in the engine bay don't line up with the TSRM; the wires on the other side of the igniter control connector are Pink -> black with a yellow stripe, and White -> black with a white stripe.

I've tried three different coil/igniter assemblies and am no closer to an answer. Any ideas? :sadbanana:

 

[StanS]

I said remove a plug (one, not all) and a few seconds of crank will not put out enough fuel to be a hazard. "If you read my first post, I noted that I don't have a spark at the coil." Then why are you looking for a fuel problem? It's possible for 2 simultaneous problems to arise, but unlikely. You used a known good ignitor with a known good coil and and good bat voltage and still no spark? Then the signals must be bad. Is supply voltage to ecu correct?

 

[StanS]

Is ignitor mounting bracket in good electrical contact with body grounjf? Check with Ohmmeter.

 

[Gargravarr]

I said remove a plug (one, not all) and a few seconds of crank will not put out enough fuel to be a hazard. "If you read my first post, I noted that I don't have a spark at the coil." Then why are you looking for a fuel problem? It's possible for 2 simultaneous problems to arise, but unlikely. You used a known good ignitor with a known good coil and and good bat voltage and still no spark? Then the signals must be bad. Is supply voltage to ecu correct?

I'm sorry for snapping at you, Stan. I was frustrated.

It looks like I do have 2 problems - I bridged the fuel pump test connector, and although the Circuit Opening relay clicks on, the pump wasn't running. I put a voltmeter across the fuel pump supply terminals (with the pump disconnected) and measured just 2 Volts! I don't get it; if I had a short, surely I would measure nothing there?

So, an update:
-Dismantled a lot of the car and discovered that Toyota use different colour wires on the UK models to those in the EWD!
-Traced the IGt and IGf wires from the igniter to the ECU and there is continuity
-Found the check connector after tracing the wire from the ECU. Bridged it, but the Check Engine light doesn't flash. Put a voltmeter on it and there is 5 volts steady
-Still can't find the No.2 Main Relay, but since there is power to the coil, I guess that means it's working
-Determined I was correct in that an old alarm was still in the car; traced the wiring and found it intercepted the coil power supply, but it was only connected to positive and ground. Found the old wiring cluster terminated behind the radio, wired into nothing. Removed the old alarm completely
-Tried spraying Easy Start into the air intake and cranking the engine. It went straight through unburnt.

So in summary:
-Still no spark
-Fuel supply problem too

What the blazes is going on here? On its own, everything seems to add up, but when put together it doesn't work.

 

[Gargravarr]

Is ignitor mounting bracket in good electrical contact with body grounjf? Check with Ohmmeter.

I have continuity between the igniter casing and the battery ground, measuring 0.6 Ohms

 

[Gargravarr]

Right, I don't know what happened earlier, but I regained the spark... and then lost it again! This car is trolling me!

Out of desperation more than anything, I went and bought another ECU (it wasn't expensive at £30), but it hasn't changed a thing.

How the spark came back:
-I put the voltmeter between IGt and ground and cranked the engine
-The needle rose to about 1V and began to flick with the trigger pulses
-I put the voltmeter on the IGf return and did the same thing, but only saw steady voltage
-Curious, I put a spark tester on #1 plug and got someone to crank the engine. The tester flashed!
-I still had the fuel pump disconnected, so I squirted some Easy Start spray into the intake, and after a few seconds of cranking the engine fired a couple of times!

I then went back to the fuel pump, checked the power connector and found 12V. Connecting everything back up... it stopped working again.

I'm lost. Really!

Things I have noticed:
-12V at the ECU power connector
-IGt pulses as expected
-IGf inconclusive
-With both ECUs, bridging the check connector does not make it blink codes. First time turning the ignition ON after bridging, the CE light flashes once and goes out. Next time it comes on solid.
-Fuel injectors are working. Could smell fuel in the exhaust

I don't know where to go from here. Things I am confident I've ruled out:
-Coil/igniter
-HT leads
-IGt/IGf leads
-Battery
-ECU
-Fuses

...what have I got left?? :ugh:

 

[StanS]

Corrossion or intermittant open on connection(s)/terminals. Check bat neg terminal to ecu ground (on ecu) with ohmmeter ON ecu and bat neg terminals. Ecu is common to spark and fuel so a poor or intermittant power or ground connection can cause your problem. Always use ohmmeter to check wire continuity. Visual is insufficient since there can be an internal break in the wire (usually at connector/terminal pins).
Tighten ignitor mtg bracket bolts 1/8-1/4 turn monitoring interground connection with ohmeter. All terminations/connector pins are suspect. Wiggle wires at connector pins to locate an intermittant. From your descrip[tion I assume that you're using an analog voltmeter which is way to go. A DVM might not react fast enough to an intermittant fault.