98 civic changed from auto to manual

Rad92

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Hi, Thanks in advance for any help you guys can offer! I bought a 98 Civic at an auction. It ran great when I got it. Broke cv joint, finally got it replaced. Now it bogs terribly if you don't baby the gas pedal. I took it to a mechanic. He said it scans as Automatic, which I kinda, new, since it has no tack. He said it would never run right because the computer still thinks it's an automatic?The car ran fantastic when I bought it tho, so I'm not sure about his "diagnosis" I just love driving this Lil car. Superfun. Reminds of my first New car 1977 Celica Gt. Compression is good, timing was set, new plugs, wires distributer, Fuel pump.. It runs OK when you finally get it up to speed, but have to downshift to 4th to keep highway speed at even the slightest uphill grade on the Highway. It backfires when u start it too, Will not Rev without backfiring till it gets completely warmed up.. Thanks
 

Pete96cxEK

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This is just a guess but try and clean the injectors, fuel rail, etc.

Also change the fuel filter maybe
 


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nd4sped

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It should run fine without the automatic transmission. You will just get all the transmission codes.
Is the temp gauges reading correctly. If the water temperature is not being read by the ECU correctly it could be dumping fuel at idle or before the war warms up causing idle and low speed misfires.
 

Rad92

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Thanks for info! It is extremely cold natured.. It won't run until it reaches temperature.. I'm thinking it might be because the original air intake system has been replaced by a k&n filter intake? Thanks for info!
 


Rad92

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This is just a guess but try and clean the injectors, fuel rail, etc.

Also change the fuel filter maybe
Hey, Thanks.. I did actually change the fuel filter when I changed the fuel pump. I haven't performed a fuel pressure test other than just breaking the line at fuel filter, seems to have plenty of pressure? I have so much fun driving this Lil car.. But sometimes I think I might be beating a dead horse.. Odometer shows 235,000 but pretty sure engine was replaced with engine and manual transmission in one package? It acts like it really wants to run, but it just chokes out when u give it too much throttle.. Thanks guys!
.
 

nd4sped

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Do a compression check with the engine cold. Alternatively you can do a Leak Down test which will provide more information on where your leak is.

To perform the leak down test you will need the proper LD tester and an air compressor that can produce enough air pressure. Read the instructions on the leak down tester carefully. If you perform this test incorrectly you can pop out the valve stem seals.
 

Rad92

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Thanks so much for the heads up. I'm thinking the cold compression test waz not great.. Like it took 25 cranks to max out into 120,170,120,170..Warm engine got these readings in 5 cranks.. Does this mean it's more likely valves than piston rings? Thanks!
 

nd4sped

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Thanks so much for the heads up. I'm thinking the cold compression test waz not great.. Like it took 25 cranks to max out into 120,170,120,170..Warm engine got these readings in 5 cranks.. Does this mean it's more likely valves than piston rings? Thanks!
Compression will only tell you the compression values, it will not tell you where things are leaking. You will need to conduct the leak down test to get those results.

Also you should be getting results in the 190-210psi range. This can also vary a little depending on the tool used. As long as you are within 10 psi of each other on each cylinder you should be fine However seeing that two cylinders are down on compression by 50 psi signifies a serious problem.
 

Rad92

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OK, Thanks for your input! I just like driving this little car so much, that I guess I'm not wanting to accept the fact that I may be beating a dead horse.. I may go ahead and get the tools needed to do a leak down test before I decide to put the ol girl out to pasture! Thanks guys!
 

Rad92

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Compression will only tell you the compression values, it will not tell you where things are leaking. You will need to conduct the leak down test to get those results.

Also you should be getting results in the 190-210psi range. This can also vary a little depending on the tool used. As long as you are within 10 psi of each other on each cylinder you should be fine However seeing that two cylinders are down on compression by 50 psi signifies a serious problem.
I talked to one of my local mechanics, and they quoted 1 hr service rate of $160 to preform a leak down test.. I'm thinking I can buy or build one for less?
Also.. I drove the car again today and have noticed a definite pattern, as it runs ALOT better when the tanks is full, As tank level goes down to around half on the Guage, I notice that it starts running worse, struggling to accelerate through the gears, Having to "baby" the gas pedal even more.. I did replace the fuel pump with a non OEM pump I bought thru ebay but it seems to work OK.. Any thoughts you might have on this phenomenon would be appreciated!
 

nd4sped

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So you replaced the fuel pump and that fixed your problem? It a 20 year old fuel pump.....

However fuel pump does not relate to the cylinder pressure readings you got during the compression check.
 

Rad92

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So you replaced the fuel pump and that fixed your problem? It a 20 year old fuel pump.....

However fuel pump does not relate to the cylinder pressure readings you got during the compression check.
HI, And thanks.. Yes I actually replaced the fuel pump a couple of years ago. The original was deceased. I replaced it with a, non OEM one that I got on ebay. Seems to work OK? I don't have tools to preform a fuel pressure test, but seems to be plenty of pressure when I break the line at the fuel filter.. The car has has been stripped of original airbox and manifold and has aftermarket K&n type air filter. So I'm thinking that might be part of the problem? There is no sensor, just a 90 degree tube coming off the intake/butterfly... The car is very cold natured, and sputters and backfires until it reaches temperature @about 10 to 15 minutes.. One mechanic told me that it's a computer problem because it's been switched from auto to manual. I know it's kinda worn with compression at 120,170,120,170.But it will go 110 on a flat road. It just has trouble accelerating. I have baby the pedal or it backfires and falls flat.. Thanks in advance for any advice!
 

nd4sped

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The compression readouts you have are terrible. 50 points down on two cylinders, is most likely your problem.
 

Rad92

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The compression readouts you have are terrible. 50 points down on two cylinders, is most likely your problem.
OK Thanks for your input. I like driving this car so much, I hate to put it out to pasture! Happy holidays!
 


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