89 camry hard start & stalling

TPS? (throttle position sensor - tells computer throttle position)

2nd guess: have you ever changed the fuel filter? "bad" tank of gas could have restricted it reducing fuel flow on open throttle 3rd guess: muffler or catalytic converter collapsed internally restricting exhaust flow inhibiting open throttle performance. Check intake vaccuum, should hold steady at say 2500 rpm and not drop (drop in vacuum being related to increase in exhaust backpressure)

Thanks, but apparently I did't explain the problem adequately. I have to doubt 2 & 3 because the engine will rev up to high RPM with no sign of fuel starvation (clogged filter)or what I would expect from a clogged catalytic converter. I was doing futher testing this AM and then found the battery was completely dead and now doesn't seem to be taking a charge properly -- problem may be related to that. Thanks for your input.

An EHT leak has the same symptoms. When the accelerator is pressed, the mixture increases in volume and density. Once the piston reaches the top of the compression stroke, that mixture is even more dense and represents, as far as the spark-plug gap is concerned, as greater resistance or reluctance for the spark to jump (across the gap) so the spark (Extra High Tension) takes the path of *least* resistance down thru a carbon track in the distributor cap or some other damaged insulation inside the distributor where the spark-coil is located..

Try running the car at night with the hood up in complete darkness. Then gun the throttle and see if there is any signs of spark leakage. Sometimes a clicking noise can be heard or corona (a dim glow of discharging gas inthe air) forms nearthe leakage point.

Some corona is normal around the spark-leads.

Jason

Tnx JJ

Now I have NO SPARK AT ALL. I've done a bunch of checks and have found nothing. I'm down to thinking the most likely suspect is the ignitor module and am looking for someone who has facilities to test it since it's rather pricey and non-returnable if it's not really the problem.

Jim H.

Before you replace the igniter, test for faults in the coil and pickups, tho in the latter case it's not likely all the pickups have failed to-gether.

Its also a good idea to confirm there is battery voltage and Earth present at the igniter when ignition is ON. Using a mmeter on a volts range will not damage the igniter.

If possible ubsing the MM resistance range,..check the continuity of the wiring from the dizzy to the igniter.

Tests for dizzy pickups and EHT orSpark coil.

Parts of this info was taken from aftermarket w/shop manual

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The ignition coil is part of the distributor. To carry out any fault diagnosis you will need a workshop manual and an ohm meter which covers quite a wide scale. A digital multometer for about $15 or so should be OK.

The distributor has 2 sets of pickups which feed small voltage impulses to the igniter which is mounted on the firewall. The igniter's job is to amplify the small signal pulses synchronised with each cylinder's power stroke commencement (or there abouts. The actual ignition timing is 10 degrees BTDC) to full 12v peak coil power-switching pulses. So there is a loom between the dissy and the igniter which contain wiring to and from the igniter. The coil is in plain site once the dissy cap is off and the cover removed.

There is a connector for the pickup coils,..but you may have to remove the ignition coil to measure its continuity ie Coil primary and secondry : 0.3 to 0.6 ohm and 9k to 15k ohm. The coil has 3 contacts when viewed as installed. Both Primary and Secondry resistance is measured with respect to the +ve terminal which is the lower RHS one. The other Primary contact is the lower LHS,...the Sec (spark output) is at the top edge.

Pickups : unplug the dissy's rear connector (closest to firewall) There are

4 contacts laid out left to right as G+ G- NE- NE+ Make sure the connector tab is at the top for correct orientation. Ohm measurements are : G+ and G- 185 to 265 ohm

NE+ and NE- 370 to 530 ohm

You will need a manual to do these measurements, if you are not experienced with this type of work.

Jason

Tnx for the reply, Jason. ( Note: Some of the "descriptions" you give do not match my vehicle.) I have measured the coil primary and secondary, and the pickup coil, and all resistance measurements pretty much match the values given in the Haynes manual. In addition I put a low current light bulb from the coil

-terminal to ground. The bulb lights indicating current flow through the coil primary to ground. I assume the bulb should flash off when the ignitor receives a pulse from the pickup coil which, I imagine, turns on a power transistor in the ignitor and thereby briefly connects the coil

-terminal to ground. The bulb does not flash when the car is cranked. But, perhaps the pulse is too short to visibly flash the lamp (?)

I'm tempted to hookup an oscilloscope to the coil primary and the pickup coil -- I would think pulses from either should be visible on the scope.

Jim H.

That's good.

In addition I put a low current light bulb from the coil

That a reasonable test, having first ascertained the coil has no shorted internal turns of the coil wire.

I assume the bulb should flash off when the

That's correct.

The bulb does not flash when the car is cranked.

Exactly. I have used an oscilloscope to measure ignition pulses from an Ford igniter. The gated (constant width) power-pulse width is in the order of millseconds and as such will not cause an incandescent bulb to flash. Trouble is there is no other light which will help here. Those cheap flourescent lights take too long to turn on due to their slow inverter curcuit response, while timing lights require a trigger from an EHT/spark lead

All I can recommend here if you cant get hold of a scope, is to use a digital multimeter on a low volts scale (20v or even 10v) which should give a jump in reading. An anologue multimeter set to a low volts range will take up a voltage reading which equates to the average DC voltage-pulses over time,..but it will be small as the igniter only fires for a very short time every second during cranking.

If you remove the sparkplugs, the cranking speed will increase which will in turn increase the averge voltage-level you are trying to measure.

So you do have a scope! Ideal instrument for this. Loosely couple the scope input to the coil output (just lay the probe near the coil so it picks-up by inductance) to ensure there is no EHT. Then you can connect to the igniter input, starting with the scope input attenuator at a high setting, then reducing this till there is a response on thescreen.

If the coil is working, the 'back EMF' or reflected output voltage may damage the scope input amplifier,..so I always start off with some "loose coupling" before making direct contact with auto-ignitions.

Jason

Tnx Jason. I connected the scope to the -coil terminal ( I forgot about the inductive kick, but the scope is an anchient tube-type so hopefully nothing was damaged.) but I didn't see a pulse. But I was in a hurry and maybe didn't take the proper steps (sweep rate, Etc.) to catch it. I also tried briefly shorting the coil -lead to ground and I did observe a spark from the HV secondary -- not a very impressive spark -- about 3/16" in length. I'm not sure how much spark I should see using that technique. Yes, I should remove the plugs to lessen the load on the starter. I want to look for codes out of the computer but the Haynes manual says to jumper E1 & T but there is no "T". In the cavities that have contacts there is a Te1 & Tt. Any idea which equates to "T" ? I'm getting discouraged. Tnx again for your help. Jim H.

Tube types give extra protection to input overload.

But I was in a hurry and maybe didn't

These pulses are quite narrow and if the CRO (scope) is not on a triggered- timebase,..you may miss them as the timebase is running un-sychronised,..but usually the cro has no problem given the amplitude of the signal (12v or so)

That is a good test provided the igniter is completely disconnected (as I'm sure you would have). I keep forgetting the igniter is switching the earth or ground side of the coil. The spark is generated as the magnetic field collapses. If you cleanly apply an earth and remove it,the spark should be quite healthy in the order of 1/2" and blue in colour. If it really is only

3/16" from the coil output/sec it may be lost in the distributor cap rotor to cylinder pickups losses. The rotor does have a small gap as it passes each plug-lead pickup and 3/16" maynot be strong enough to jump across it and still be strong enough to jump the spark-plug gap.

For the moment, Ithink you can assume the coil is OK for purposes of determining if the igniter is working. I'd hook everything up again and try to get the CRO settings such as input voltage (taking into acct the probe attenuation if relevant- you maybe using a direct-probe), a slow timebase eg 50 ms/cm. Then test for igniter switching again at the coil.

I'm not sure how much spark I should see using that technique.

I cant comment on the designations used in the '89,..but at this stage if I was you,..I'd concentrate on the igniter. You're almost there.

Jason

Again, tnx for your reply.

The first time I tried the short-to-gnd I forgot to disconnect the igniter

-- when I then did the spark appeared to increase.

Your remarks about the gaps the spark has to jump are well taken. I certainly would like to see more spark ! I'm not getting what I would call a "hot" spark.

The scope is a triggered scope -- I need to look for the pulse in trigger mode. I almost purchased an ignitor on ebay the other day but got outbid

-- probably should have did the "buy now" option. But I hate to purchase a non-returnable "expensive" part without being confident it's really the problem. And I suspect if I wimp-out and have the car towed it'll probably cost more to fix than the car is worth.

I've been fixing personal and family cars for about 50 years -- I think should have quit before this one. ( I have a son in Minneapolis who owns a '70 Mustang Mach I and I'm frequently called upon to fix that over the phone. Agggh )

If I find the problem I'll let you know -- perhaps we can both learn something.

Happy trails, Jim H.

All my problems originated in the AFM, which I originally thought was causing the stalling, Etc. The Vc was shorted at the AFM. With my limited knowledge of the system, Etc., I would never have expected the AFM fault to shut down the ignition and check engine light. "Jeff from Redding" had experienced a similar problem in the past. Jim H.