mully006

Hello,

I have had this problem for a while now. Whenever I get on the gas the engine will shudder and lag until the revs build to around 3-4k. Then the engine is normal. It has just enough power to drive at highway speed in fifth gear, however to go up any kind of hill on the highway I need to go into fourth.

The spark plugs are showing a lean condition on every cylinder, I think this is the cause of the shuddering and hesitation. Also the problem started after the engine overheated, however I am not convinced that the head is warped, from the results of the compression test/leak-down test.

-compression test - ~195 on all cylinders
-leak-down test - ~18% on all cylinders
-Test TPS - works correctly 0.5V to 4.5V-WOT -still need to test the ground and supply voltage, I can't remember the results
-Fuel Pressure - It was right on speck, I do not remember the value
-Replaced the PCV valve
-Ran a full container of Sea Foam through the vacuum system
-Took apart fuel rail and cleaned the fuel injectors. The was black residue all around the injector tip. I cleaned that off and I set them sit in SeaFoam over night.
-Ran fuel injector cleaner


Other Stuff
-If I drive for an hour I get codes 7 and 43, that TPS sensor and Fuel Supply System.
-The engine runs the same with the TPS disconnected.(reving it in neutral at least I didn't drive it)
-I have a vacuum gauge connected and it shows the following problems
--Fluctuates rapidly by 1Hg all the time.
--At idle is at around 21-22Hg
--intermittent drops to ~19Hg at idle
--When the engine is shuddering the vacuum fluctuates rapidly between 0Hg and a normal 'under power' value between 5 and 15Hg
--If you let off the throttle quickly the vacuum only climbs to around 24-25Hg


Any help would be really appreciated. I am running out of things to test. And I do not want to throw parts at it.

EDIT:
Car:
1993 Honda Civic DX 1.5 Hatchback
D15B7 Engine
5-Speed

ezone

I wonder where you connected your gauge.
If you have it on an individual manifold runner, you COULD be seeing that particular cylinder draw its intake stroke.

Connect as close to the throttle body as you can.



How about valve adjustment?

Does it "drop a cylinder"? Dead miss under load?

ezone

Monitor your TPS value and see what it's doing when it sets a code?

Is this related or unrelated to the other part of the complaint? Sounds like more than one problem.


I really hate pre-OBD2 troubleshooting LOL

mully006

I am connected right off the intake manifold. I pulled off the brake booster line.

I not sure. I haven't touched it, the the previous owner might have.

I don't think so. I not sure how to tell.

mully006

I'll give this a try. I waiting for my voltmeter it should be here in a day or two.

I think they are both connected. I think the code 43 is related to the computer detecting that there is a lean condition.

ezone

A dead miss would be the same as removing one spark plug wire and trying to drive it. One cylinder completely dead, not contributing.

I wonder if this is the feeling you are trying to describe when it loses power... (intermittent, maybe load related)

mully006

It not like a cylinder is not firing. It more like when you **** into to high of a gear. If you add more gas, the rev's do not build and the engine glugs and shudders.

ezone

Same thing would happen if the engine were only running on 3 cylinders, wouldn't it?


Got 2 voltmeters?
Connect and watch the O2 sensor and watch the TPS as you drive?

mully006

I don't know. Its beyond me. I know that it didn't sound/feel like when I ran a quick test on the fuel injectors by unplugging them one by one. The problem does not feel like when there is one of the injectors unplugged.

ezone

Ok, then it seems like monitoring those sensors would be a good next step.

mully006

Thats what I am going to try to do this week