Hello, this would be my 1st honda ever. I have been a auto tech for 14 years (no import background)and have run from these cars my whole life.....well as fate has it I now own 1.

This is a 91 Civic Dx with a 1.5L this is a 5 speed. Car is 100% stock. The owner was selling due unkown reasons......well now I know.

Lets start. Take off car runs fine. Has a surge at ideal from about 600-1500 rpm....no biggie. Has a SES light. Take off from stop sign and car falls flat on it's face. Next stop air up tires and check all fluids and top off. Every thing was connected under hood and had a good contact, checked a few plugs for corsion and oil but were fine.

Take off car WILL NOT rev, it was as if all 4 cyclinders were missfireing at the same time...very strange. 25MPH was top speed. Stop unplug all sensors and check contacts looks good. Took off car would half A$$ run but acting lick it had jumped time. Low end was fine nothing past 1500rpm.

Trying to get to a budys house(honda guy) it was as if some 1 fliped a switched and the car ran PERFECT for the last 1/2 mile. My budy gets codes from ECU and has 3 codes. Can;t rember the numbers. Was a TPS,IAC and BARO pressure. Car still running ok at this point.

While driveing the light on ECU blinks didn't seem to have a patern but I was driving so hard to say.

Get on highway car runs 70 mph just fine for over 40 miles. As I get off high way I hit a pot hole and the car dam near dyes. The missing has become more like you are turning the key on and off VERY fast. I was not able to check if it is loss of spark or fuel. This is not a slight issue.........think turn the key off and on 30 times a minute while driveing. The issue was not related to speed of the car OR throtle angel. You could not drive out of this and could not make it go away. Rev the car up in nutrel and had horid crackling sound out intake AND exhaust at the same time.

It is now sitting at my shop, as I pulled in the parking lot it was as if that magic switch was fliped and car ran fine again. No poping or crack out intake or exh.

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Printed off a wiring diag and started testing. 1st was TPS sensor. key on engine off .78 volts. Running at ideal was .56 votls. Tested for dead spots or drop outs with the engine off AND running. 4.7 volts is peak at WOT. NO DEAD SPOTS.

The car is acting up during 2nd half of the test and still nothing. If you rev car even 1/4 throtle has sligh craking out intake for 2-3 seconds and then revs up fine. A few times was able to hold gas to the floor and car woudl not rev more then 2K rpm and out of clear blue revs and won;t act up again.Car also had a MAJOR surge still. This is more not a slight lope, more like steady rolling of the throtle from 1K to 2K. As soon as the engine is under load seems fine..... drive around parking lot and sparks bucking BAD. Think drivers ed teaching how to drive stick type bucking. Can not carry a steady speed under 20 mph with out had bucking.

TPS has ground, it seems to share with 2 other sensors and they also have GOOD ground. There is a 4.75 volt input to sensors.

I had cleaned the TB and the cold air coke plate(?) this had no effect. Disconected the IAC and the ideal did not change. Blocked vacume port of IAC to intake no change.

There are NO broken or leaking vacume lines and the power boster is not leaking. Have sprayed every thing down looking for a cracked intake and nothing.

Coolant is full as well as oil. This does not have a MAS sensor(no clue if any hondas do).

The timing belt has not jumped(checked marks).

HAve been told these cars have distrubtior issues. What is that about and what issue does it cause when it fukes up ?

I SHOULD have the conector I need for my Snap On scanner tommorow. Have never had the need so never bought it Maybe that will help shed some light but I'm not even sure what the data stream would look like if it has 1. I also will have my Snap On vantage back for doing componet test's.

I will figure this out sooner or later but was hoping some 1 here could save me a day or 2 of work. MAybe there is something I'm missing as I'm not used to working on these cars.

Any idea's or tips would be GREAT. Sorry for the spelling been a long day and in a hurry.

 

HAve had a few hours to run s few tests.

1st it looks as if some 1 has realy messed up. The IAC and Air temp sensor had the plugs swaped. Well the air temp sensor has the end blown off it. Cleared codes. The only code that sets now is Code 10 Air temp sensor.

Does any 1 know what the ohm value for the air temp sensor would be for say 60 dregrees ? Had to order a sensor and would like to see what else happens.

With the plugs in correct places car still surges at ideal. I have run a bunch of test on the distubator and come up with little. AC voltage running and cranking test ok. Restaince is in range. Dist shaft is not loose and no oil leaking in it. HOWEVER the only thing that seems strange is the FREQ test(hz) is wacky. It will be reading correct and just drop out for a second then right back. The hz will not hold steady. As the RPM increase the freq starts read higher then it should. Also the freq seems to drop out every know and then for a second. I have NOT been able to see if the freq drop out happens at the same time car starts missing.

MAP sensor tested out in range for voltage and vacume. NOW for some reason when the map sensor is unpluged and the car started it ideals FINE. No surge or lope. I would be lead to suspect that it is faulty but all testing shows it is working as designed. Also the fact that parts for this car seems to cost 10X's what there worth.

ANY ONE PLEASE HELP