gte718p

I'm having issues with my 86 4runner 22re.

It is lacking power, getting horrible gas mileage and sounds like it is missing on a cylinder. The exhaust smells like straight fuel. Occasionally the truck will start surging at idle and then die if you don't get in the gas. I'm not sure if it is related, but the truck is hard to start cold. It takes three time cranking to get it to start. It starts consistently the third time cranking if you give it some gas. When I had the radiator cap off to do the exhaust gas the coolant was really surging once the thermostat opened. I'm not sure if that is normal or not.

I've so far I've check the plugs and wires. All the plugs are good, gap is .035, all plugs are firing, wires and plugs are NGK.
Intake and exhaust valves are set IAW the sticker undressed. I can't remember the numbers off hand, but they were good.
Compression is 180 +-4 across all cylinders
Idle is rough but it is set at 700 rpm and +5 with the terminal jumped.
Vacuum is 14 psi at idle.
No indication of exhaust gas in the coolant.
I haven't check fuel pressure yet, but there is very good return flow at idle

The next things I'm going to check are the throttle position sensor and then the AFM.

Has anyone seen anything like this and or have any suggestions on where to go next?

osv

what you look for with vacuum testing at idle is to see if the needle is jumping around, which could indicate a valve problem(?).

is it throwing any codes?

gte718p

No codes. Vacuum is fairly stable.

I forgot to mention, I've checked the cold start injector. It doesn't appear to be leaking. I have it disconnected.

Terrys87

iTrader: (1)

I am currently working on a similar problem. Pull one plug wire at a time and see if you can track it down to just one cylinder not firing. If that is the case, you need to see if the cylinder is not getting spark or the injector is not firing due to be bad, clogged or no signal to the injector.

As far as the AFM, I have never had an AFM to throw a code. The only way to get a code from a bad AFM is when it is not connected. I have had some bad AFMs. The only real way I know of seeing is if you have a bad AFM is to do some resistance checks per a Haynes Manual or the Factory Service Manual if you have one available.

Another thing I have had bad out of the box is plug wires, even being new. I would suggest running a resistance check on your plug wires. Especially if they are after market brands. I prefer the Denso wires and you can get them shipped to the house for around $27 from ebay. I think when I priced the same wire kit from my local Toyota dealer they were $83. Denso is better then the parts store brands in my opinion.

As far as you TPS, I would run the checks per the manual and see what the results are. If it fails, I would suggest popping for a new one. I have tried to clean old TPS sensors or use them from a salvage yard and in my opinion on a truck with a few hundred thousand miles on it, it probably needs replaced. Look at how many times you are on and off the throttle in a single mile.

As hot as it is in most parts of the country, the Cold Start Injector should not be an issue. Depending on where you live, if it is cold enough to need the Cold Start Injector, most cases the Injector is good but the Timing Switch that controls it is bad. It is the brown sensor on the front of the Intake. Cleaning the hard water build up off of the sensor can fix some cold start issues.

You dont say how many miles you have on it but with the age, how is the EGR and the carbon build up inside the hoses, ports, and Plenum? Probably needs cleaned.

Not a fool proof way of checking fuel flow, but I take the rubber line that comes off of the Fuel Rail and run the end attached to the firewall and stick it in a plastic water bottle. It should fill a bottle in about a minute to a minute in half.

gte718p

I pulled the return line on the pump, plenty of flow. Hoses are all new. I probably should pull the plenum. Mileage is 246k

RAD4Runner

My hard starts came back, and at the stop, the idle was so low, I could hear my C.O.R. click. I could also smell the exhaust. Even after I replaced the air filter, problem remained. Finally cleaned the Throttle body flap and where it contacts the bore. Problem and strong exhaust smell seem to have gone away.

gte718p

I pulled the intake on my old 4runner. The intake was horrible. Three trips through the machinist hot tank failed to clean it up. It would probably be worth pulling the throttle body and intake on this one as well.

Thank you for the input. I'll give it a shot next week.

RAD4Runner

Oh, BTW, when I decided to look more closely into my intermittent (would come and go about once a year) hard-starts / rough idle, installed a fuel pressure gauge piggybacked on the CSI.
Someday, I'd like to replace that with a sender to dash so I can read fuel-pressure as I'm cranking and in real-time.

osv

it's an '86, right? if you are going to go thru the hassle of cleaning up the intake, do it with the later 22re straight plenum/tb, because it has the superior warm-up circuitry.

oven cleaner works, but some types of oven cleaner are reputed to dissolve aluminum, although i suspect that it's a slow process.

i was able to re-use the factory tb cable that was in my '86, with the later tb/plenum, by cutting off the tip of the cable with a die grinder, and using a barrel nut from the dorman help section... you only have to cut off a tiny bit, check the length carefully.