20 replies to this topic

[GeezRX]

'86 3G Si - fuel injected obviously - daily driver and currently the only vehicle I have available for use. In the last two weeks it has begun randomly stuttering and trying to die, typically at low to mid speeds (most of my driving is highway speed and usually 40 miles or more with little to no stopping). It will stutter and try to die but if I can keep the gas pedal depressed it will clear itself and go on. If I let off the gas completely it will die but will start right back up with a couple cranks. Between the stuttering episodes it revs fine, runs steady and pulls strong through the gears. Since it was time anyway, I replaced the fuel filter to see what effect it might have but it continues. Two days ago as I left for another 40 mile highway trip home, I got a PGM/FI light that stayed on steady the whole way home but the car ran fine, no stuttering or anything out of the ordinary. I checked the ECU for codes when I reached home and found that lights 2 and 4 were lit. FSM indicates this is a possible issue with the Intake air temperature (TA) Coolant temperature sensor (TW) - which I have yet to locate on the engine! I cleared this light/code from the ECU, replaced the fuel filter and rolled off today to see what transpired...right after leaving home, same thing, stutter-clear-40 mile highway trip with no further issues. On the return trip this evening it stuttered and died 3 times (each time I was in a position where I could not keep on the accelerator) before I reached the highway but started right up again each time. Third time was right at the entry to the highway and after restarting it ran like a top virtually the whole way home save for about six blocks from the house when it stuttered one time only, cleared itself immediately and continued on like nothing had happened. I'm going to assume it will end up being the electric fuel pump (Denso installed new 10/2012) but it sure isn't acting like I'd expect a failing pump to behave? If you've had any experience with these symptoms and can offer anything that will allow me to quickly get this addressed without lengthy test/down time, which I don't currently have, please chime in...it will be greatly appreciated! Thanks in advance to any respondents!

 

Skip

[1985 CRX SI]

 I would rule out the fuel pump and related anyhow because you said it runs fine with the PGM-FI light on. 

 

I would locate the  Intake air temperature (TA) and unplug it. This forces a PGM-FI light. It is easy to get to and is close the the brake master cylinder on the #1 intake runner. Drive with the PGM-FI light on. If you have no drivability problems on your normal round trip.  

 

Lights 2 and 4 are coolant temperature sensor.

 

Lights 2 and 8 are Intake air temperature.

[1985 CRX SI]

This looks like the right part. Not 100 percent sure. Check first.

 

https://www.ebay.com..._from=R40&rt=nc

[gtpilot]

This looks like the right part. Not 100 percent sure. Check first.

 

https://www.ebay.com..._from=R40&rt=nc

 

That may be the correct part, I can't remember the connector configuration - it is located on the end of the cylinder head by the distributor.  You can use a multi meter to check to see if it is in operating range...seems to mt that it should be in the 2-3K ohm range "cold" and 300-500 Ohm range when hot.  If you can locate the sensor and pull the connector off of it take a reading first thing in the morning before driving it and then take another reading after getting it fully warmed up.

[GeezRX]

Thanks gentlemen to both of you for the responses! Sorry I haven't gotten back to post before now but I've been stuck in the country at my daughter's ranch with no ability or time to check on it. I will ohm out the temp sensor and verify it's condition first. First, I don't have a "systems checker harness" (any availability on one of these?) so can't verify as directed (in the FSM page 11-58) at the ECU end. I can and will check voltage at the Red/White - Brown/Black wires at the coolant temperature sensor. If this shows normal, it refers to page 11-68 of the FSM and this shown below...

Ok, this is the sensor on the intake manifold, which after reading your posts I easily located. Should this be the culprit...and I suspect it will be...can anyone steer me to purchasing a new one? Anyone supply an original part number? I can't find it anymore on the various factory part sites in the illustrations. I know I have seen these on the aftermarket previously but can't find any listed now. They are a fairly uniquely shaped sensor and none of the "sensors" available for our cars that I found even remotely resemble it. Thanks again for the input on this!

[1985 CRX SI]

The number on the lights for the ECU are arranged (1,2,4,8). You Said " found that lights 2 and 4 were lit " 

Lights 2 and 4 are coolant temperature sensor.

[GeezRX]

Ok, this took me a bit but I think I get it now. This illustration that I posted is an either/or procedure for both of the sensors where I was going by just the pictured sensor. I know the coolant sensor is still available from the aftermarket so I'll run the ohm test tomorrow and see what transpires. Thanks!

[1985 CRX SI]

http://estore.honda....2&dl=206582#015

[1985 CRX SI]

https://www.ebay.com...2013/1222268268

[GeezRX]

Thanks for the links and your efforts '85 CRX Si, I hadn't used the Honda estore site before...it's added to my bookmarks now! I'm headed out shortly to address the issue with this new found information.

[GeezRX]

Well...obtained a nos intake air temp sensor and after a ridiculous amount of time and multiple attempts, getting a vendor to send me the correct nos coolant temp sensor, I installed the replacement coolant sensor and topped up the coolant level only to find when attempting to start it that a vehicle which had previously started every time on the first crank, will now not start at all. It cranks and cranks and randomly will almost fire but never actually does. The screws holding the intake air sensor to the manifold will not budge even after repeated applications of PB Blaster...I'll have to get my hands on an impact driver to see if I can get them loose without damage to the manifold. Scratching my head now on what direction to take on this problem.

[PuddleSkipper]

How's the spark, air, and fuel?

[gtpilot]

It should still start even with a faulty sensor, so something else is going on.  Just plug in the old sensor (don't bother to install it) and I bet it behaves the same?  Did you attempt to measure this sensor and the Coolant Temp sensor (code 2/4 is the Coolant Temp sensor code)?

[PuddleSkipper]

Guess 1) bad ignitor Guess 2) bad mair relay. Use Kroil for penetrating oil, it is by fr the best stuff i have ever used. You can also make it, i know it is 1/2 ATF fluid and 1/2 solvent like acetone, theres a Chrisfix video on youtube about it

[Sinub]

Any updates? Your initial symptoms sound a lot like mine with sputtering and hesitation although when it would stall, a bunch of black smoke would come out of the tailpipe. My problem was a mix of a bad ECU and coolant temperature sensor.

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