Intermittent Difficulty Starting Engine

[Mister O's MR2]

I hate to start a new thread on this, but none of the threads I have searched applied to my case (at least, none of the ones I found).

My car has 105k miles, I've owned it since new, it is only driven about 900 miles/yr at present, and has 8-month-old battery.

After doing a major maintenance job (November, 2007) on my '87 AW11 normally-aspirated 4AGE, I began to have starting problems at times when the engine was warm. The other day, I had the same problem when the engine was cold.

The starter cranks strongly, but the engine won't start.

My maintenance job consisted of: replacing the timing belt, tensioner pully, water pump, distributor cap and rotor, drive belts, spark plugs, O2 sensor, and air filter (all Toyota parts except for the O2 sensor); adjusting the valves, timing, and idle speed. I do my own maintenance.

After completing the maintenance work, the car started right up and ran fine. The next day I started it up, went on a 5-mile warm-up run, then took it to the smog-check station. When it became my car's turn, the tech couldn't get it to start. He took the next car in line while I attempted to get it to start.

I got it to finally start and it passed the smog test. A few weeks later I again had a problem getting it to start while the engine was warm. This happened about 3 more times, then no problem after I purchased a new battery 8 months ago (needed replacing). Then the other day, it wouldn't start in the garage as I was leaving for a doctor appointment, so I took my other car.

If I drove the car every day I would probably have more difficulty.

Since it is intermittent, and I usually am not at home with my tools when it happens, I don't know what to start checking--especially since, ignition-wise, almost everything replaceable is new (the plug wires are not original, but [U]are[U] Toyota brand).

BTW: in 2008 I only ran three tank-fulls of gas through it, so it could be our oxygenated gas here in California getting stale. I do keep the battery on a Battery Tender.

Any (pertinent) ideas would be welcome. No, I don't want to sell it. It still looks new with original (red) paint.

[toyotaspeed90]

You gave a couple clues at to what it could be, but you would need to give more information.

First thing that pops in my mind is the gas -- gas has a specific octane rating, and the higher the octane the more difficult it is to ignite. Further, as gas gets older it's more difficult to ignite as well. When gas is difficult to ignite for an engine, once it starts it will keep running.

You could try running some heet or iso heet through to see if there might be some water in the tank. It's about $1-2 a bottle, so even if it doesn't help it's good to do (especially if the car sits).

Next thing I would have to ask is how long do you crank it when trying to start and does it sound like normal (up to speed) when cranking?

[Mister O's MR2]

I am using 87 octane regular fuel. 90% of the current tank is less than 2 weeks old and was put in after a 30-mile drive. The recent cold-start problem happened the very next time I went to start the car after the fill-up.

I'm not an expert on fuel, but I don't believe that octane has a noticeable effect on ease of igniting. I believe that it does have an effect on pre-ignition.

I've never heard of Heet, but I will look for it.

I cranked the starter for 5-10 seconds about 3 times. With a fairly new and fully charged battery (I had it on a Battery Tender), it cranked over at normal speed.

I didn't have the time to continue, so I got in my other car to get to a doctor appointment on time.

[toyotaspeed90]

Originally Posted by Mister O's MR2

I
I'm not an expert on fuel, but I don't believe that octane has a noticeable effect on ease of igniting. I believe that it does have an effect on pre-ignition.

I've never heard of Heet, but I will look for it.

I cranked the starter for 5-10 seconds about 3 times. With a fairly new and fully charged battery (I had it on a Battery Tender), it cranked over at normal speed.

Heet is good to use on any car/boat/rv that has sat for a while.... it's basically rubbing alcohol...... (hence the Iso in iso heet).

pre-ignition is caused when heat from the combustion chamber ignites the fuel without the spark plug (like a diesel) -- the higher the octane the more resistant the fuel is to ignite (hence why higher compression engines that create more heat in the combustion chamber require higher octane fuel).



if it cranked at full speed and wouldn't catch you shoud check a few things -- check to make sure that the cap and rotor still look good internally (easily come off with an 8mm socket and extension)... make sure there isn't any excessive corrosion or wear on the contacts....

Next make sure the coil wire seems to be in good condition. If you haven't recently, replace the spark plugs (just a good idea always).

If all checks out then I would suspect that there's a problem with the cold start injector sequence.... there's a thermal switch and a 5th injector that either can have problems, and if so then the extra fuel required to start the engine may not be getting into the intake. (this is a really basic EFI setup to compensate for extra fuel being needed -- kind of like an old carb that has a manual choke)

[Mister O's MR2]

Originally Posted by toyotaspeed90

if it cranked at full speed and wouldn't catch you shoud check a few things -- check to make sure that the cap and rotor still look good internally (easily come off with an 8mm socket and extension)... make sure there isn't any excessive corrosion or wear on the contacts....

The cap and rotor were replaced during the major maintenance, and are Toyota parts.

Next make sure the coil wire seems to be in good condition.

That is the only secondary ignition wire that has never been replaced, as far as I can remember. The spark plug wires were replaced at one time. Maybe it's time for replacement again.

If you haven't recently, replace the spark plugs (just a good idea always).

The spark plugs were also replaced at the same time as the timing belt.

If all checks out then I would suspect that there's a problem with the cold start injector sequence.... there's a thermal switch and a 5th injector that either can have problems, and if so then the extra fuel required to start the engine may not be getting into the intake. (this is a really basic EFI setup to compensate for extra fuel being needed -- kind of like an old carb that has a manual choke)

That's something I was unaware of. My automotive training was in the era of carbs and chokes.

I'll read up on that in the repair manual.

Thanks.

[brandon_mr2]

My 89 na is a daily driver and i have that same exact problem. I have posted the issue on here before but nobody has been able to come up with a solution. It only has a hard time starting when it is warm. i live Kentucky so i don't use oxygenated gas, my car is completley stock and all of the maintenance is up to date. 134,000 miles, timing belt, plugs, wires, cap, rotor, fuel filter, air filter, fuel pressure regulator, radiator cap, gas cap, seafoam treatment, battery, valve adjustment, throtle body cleaning, fuel injector cleaning, has all been done within the past year. this issue is driving me nuts, especially when people are telling you how great your car looks but then it won't start. any help would be extremley appriciated. this forum is by far the best on the net.

[toyotaspeed90]

Originally Posted by brandon_mr2

My 89 na is a daily driver and i have that same exact problem. I have posted the issue on here before but nobody has been able to come up with a solution. It only has a hard time starting when it is warm. i live Kentucky so i don't use oxygenated gas, my car is completley stock and all of the maintenance is up to date. 134,000 miles, timing belt, plugs, wires, cap, rotor, fuel filter, air filter, fuel pressure regulator, radiator cap, gas cap, seafoam treatment, battery, valve adjustment, throtle body cleaning, fuel injector cleaning, has all been done within the past year. this issue is driving me nuts, especially when people are telling you how great your car looks but then it won't start. any help would be extremley appriciated. this forum is by far the best on the net.

if it doesn't crank it's due to a heatsoaked starter ---- somewhat common and an easy fix.

if it cranks, read through what I posted as the CSI circuit is pretty important.

[Mister O's MR2]

Yesterday I went to start the MR2 and it started immediately on the first crank.

I hadn't done anything to it (other than re-connect the Battery Tender) since it didn't start a couple of weeks ago when I was late for a doctor appointment.

Drove it 20 miles, parked it for about half-an-hour, then it started right up.

Drove another 20 miles, ran a few errands (with 4 re-starts) and everything was fine.

Came home and changed the oil and filter--and it started right up again.

I may never find the problem until the cause becomes permanent.

[Mister O's MR2]

A couple of months ago, I replaced the fuel filter (for the second time since new) because my starting problems (see above) were getting worse (read: 4 fails in 5 tries while running around doing errands one day).

Car started fine, then about a month later, the starting problem returned briefly (one time) and I have not driven the car since, other than pulling it out of the garage and back.

Per a previous suggestion, I have been putting HEET in the fuel about every three months, since the car sits so much (I have only filled the gas tank 3 times per year, the past three years!).

I'm wondering if my problem could be corrosion in the fuel tank (I believe that it is made of steel) since the car sits so much the past 8 years. I know that water in the fuel will collect at the bottom of the tank.

What do you all think? How would I check?

I didn't notice any small rust flakes come out of the old fuel filter inlet when I replaced it.

[Russell D]

when you have issues with the car not starting is it ever raining or did you recently wash the car? I don't know how the engine lid is designed on the mk1, but on mk2's the genius engineer at toyota designed the rain guard to dump all the rain right on the distributor...

I would take the cap off and check the rubber gasket for a tight seal on the distributor. If all that looks fine and you find no signs of any water inside I would look at the meta pickups where the rotor contacts the cap.

[Mister O's MR2]

Originally Posted by Russell D

when you have issues with the car not starting is it ever raining or did you recently wash the car?

This car has been a garage queen the past 8 years, and hasn't been in the rain since 2001.

I am thinking that I should check the distributor anyway, since this problem started immediately after performing a major tune-up (see my original post).

Thanks for the reply.

[ModifierMR]

Check your timing, and Cold start injector.

[Mister O's MR2]

Originally Posted by ModifierMR

Check your timing, and Cold start injector.

I adjusted the timing per the BGB back when I performed the maintenance mentioned in my original post.

I think someone else has suggested the cold start injector, but I cannot remember why I didn't check it. Maybe because I can't find it?

The BGB is good, but lousy at showing locations of components.

Thanks for the reply.

[ModifierMR]

Cold start injector is located on the Plenum (top part of intake manifold) on the front face. It has a small fuel line from the fuel rail. Its held in with usually 1 or 2 bolts and has a 2 pin electrical plug.

Pull it out, and see its stuck (very similar to an fuel rail injector). If it doesnt look stuck then test to see if it works properly by applying voltage.

Lastly, plug it into the harness and have someone try and start the car while you look to see if the Cold start injector fires (when cold outside lower then 50 or so.), or doesnt fire (when warm outside)

[ModifierMR]

http://opc.mr2oc.com/online_parts_ca...ne/efi%201.GIF

That is a parts diagram that shows the cold start injector. It is part 23260 in the lower left.