mattbmaine

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low idle no power
* #1 *
01-17-2015 09:41 PM by mattbmaine
I've searched the internet and only came across one answer. The map sensor.
I got a 96 Honda hatch with a b18 bored to a b20 Frankenstein motor. Completely built ground up. Ii have been driving it for a little while and noticed these problem's any help would be great.
When I took it out it was running great. Then I noticed power loss. Great amount of power loss. I stopped to check it out couldn't find anything so I took off again then I noticed it was getting warm so I pulled off and filled the tank and let it cool off and I was on my way home. Stated going and it was idling really rough. And when I stopped at a light the car wanted to cut off. So I had to hills the clutch in and give it gas. Never did it do that before. Then it stated over heating so I pulled off again and waited for it to cool. When I got home I noticed it used a half a tank of gas in about 10-14 miles. It has no power in r and very little in drive. I put a new map sensor on it and it would not even turn over. The old map would turn over but would idle really rough. Anyone have any ideas on what the problem is?

ezone

Overheated.....

Blown head gasket? Coolant getting into the cylinder(s), causing hydrolock?


What codes does it have?

mattbmaine

I have not done a code on it. It's a obd1 and do not have the computer. I'm will check for coolant in the oil. I'll drain it and see.
The problem came before the car over heated overheating was the last symptom.

ezone

Does it still crank? If so, then see if the coolant is low.. And check cam timing/timing belt for being out of time

If it can't crank, then remove the spark plugs. NOW see if it will crank...and if it blows a geyser of antifreeze out of the engine when you do.

mattbmaine

It does crank and turn over with the old map sensor. But does not with the new. I looked at the oil and didn't see any coolant on the dip stick or under the cap. I rolled my finger in the head and didn't get any coolant.
Timing was something else I was thinking but wanted to see if anything else could be the problem.

ezone

When you say 'turn over', you mean the engine runs?

Odd. Old part is still good, cheapo new part is bad?



Sure......but you haven't given much solid diagnostic information to go on here. I'm making guesses based on how you described it in the first post

mattbmaine

Yes the engine runs with on old map sensor but it runs really rough. It hesitates and the rpms slowly go up with the gas pushed ask the way to the floor.

I thought that new old was shot so I picked up a new one the old ran the engine and the new sensor would only crank. So I thought maybe that one is bad so I picked up yet another sensor and it does the same thing.

What I was thinking tell me if I'm wrong.
That there is a vacuum leak that the ran the old sensor and since the new sensor is right with has and Air flow that a vacuum leak would be a issue.

ezone

It's not a vacuum leak problem.

You taking wild guesses like this is the equivalent of having a blindfold on, trying to hit a piñata. That's tied in the top of a tree. In someone else's yard.

And trying to guess when there's a Frankenstein engine involved ... is like......a moat dug around that yard.

LOL
sorry it just came to me like that....

You don't NEED a computer to read codes on OBD1.
It helps tremendously when the right diagnostic computer is available, but few have access. Most people check for faults by blink codes.

Dang, I swore I made a reply on this thread saying to check the cam timing. I guess it must have been a different thread. My bad.

Absolutely-- you need to check cam timing. And if it somehow got out of time, figure out why it happened.

mattbmaine

Would the new map sensor not work due to the timing being off?
My head gasket is good

ezone

MAP sensor reads intake manifold vacuum.

If the camshaft(s) timing is wrong, manifold vacuum drops. A lot.

Map then reads the low vacuum, the computer interprets that as a load (that's not really present), and injects a lot of (unneeded) extra fuel because that's what it's programmed to do.

Then it may set code(s) for being too rich (or an O2 fault if OBD1), along with having a lack of power (sometimes minor, sometimes major) because the cam(s) are out of time.

Why does the old one still let the engine run?

I dunno.
Check cam timing and see if it's wrong.

mattbmaine

[QUOTE=ezone;4678198]MAP sensor reads intake manifold vacuum.

If the camshaft(s) timing is wrong, manifold vacuum drops. A lot.

Map then reads the low vacuum, the computer interprets that as a load (that's not really present), and injects a lot of (unneeded) extra fuel because that's what it's programmed to do.

Then it may set code(s) for being too rich (or an O2 fault if OBD1), along with having a lack of power (sometimes minor, sometimes major) because the cam(s) are out of time.




That sounds like ask my problems cam timing check in the morning.