So i have this 99 integra ls in the shop right now that is really kicking my butt. It came in with a miss fire code and really sputters under a load. If i start it up and just let it idle in park it will idle alright, maybe a little miss here and there but when i rev it up its really doggy or if i put it in drive with my foot on the brake it will barley stay running. Here is a list of things i have done to it thus far...
-different head (with all new gaskets to do so)
-different coil
-new timing belt and double check timing
-different map
-tested tps volts and percentage
-tested fuel pressure
-new fuel filter
-new plugs, wires, cap, and rotor
-different internals in the distributer
-adjusted valve lash
-unhooked vacuum line from fpr and the pressure when up
-pcv
If you have any kind of input it would be greatly appreciated!

 

so today i tried a different ignition module, different injectors and nothing. When its under a load cylinders 1 and 3 are dead.

 

anyone??

 

Did you put it on an oscilloscope?

 

The brake booster uses intake vacuum to increase brake pressure. If pressing the brake causes the engine to struggle, that means there is either a vacuum leak or some other cause of an incorrect air/fuel ratio. Check the MAP sensor signal voltage at idle when the motor has completely reached normal operating temperature. Once you've verified that there isn't enough vacuum, start pinching vacuum lines closed, testing the idle valves and checking gaskets until the leak is located.

 

Its not when i hit the brake, its when i power brake it. Under a load cylinders 1, and 3 die right out.

 

You should perform a few tests even though you'd be testing some parts you've already replaced, just so you can be certain that systems are functioning correctly. I would check the compression first. If that's ok then check your spark. Either get a spark tester or:

Disable the fuel injectors and get a new or known good spark plug. Set the gap of this plug to your vehicle's specifications and make sure it is clean afterward. Wear gloves (welding gloves work great), preferably with latex or nitrile gloves underneath, and remove a spark plug wire from its plug. Connect the good plug to the end of the wire and hold the plastic deep-well tube at the very tip of the wire end with the threads of the plug touching bare metal on the valve cover. Have an assistant crank the motor while you watch the spark, carefully keeping all body parts away from the plug, motor and car body. Different types of plugs have different colored sparks but usually a good spark is a thick, strong flow of bright pink or is at least bright. Little blue or pink "lightning bolts" indicate a weak ignition. Check all four wires. If the sparks at all of the wires are weak, try holding the threads of the plug against the battery negative post to see if the better ground makes a stronger spark. This will test your entire ignition.

You follow a similar procedure when using a spark tester. I assume you aren't losing any fluids. IMO you should still check the MAP sensor output voltage at idle when the motor is completely warmed up to normal operating temperature. Please post the voltage and the RPM the motor was at. You may also want to check and compare the fuel injector sprays or have them cleaned & tested professionally.

If you think of any other info regarding how the problem is affected by RPM, temperature or anything else, please post it up.

 

I would agree that a compression test might give you some useful information. What tests have you done to determine that #1 and #3 are the ones that are misfiring? Are you a technician? Is this your car?

 

I am a technician and this is a customers car. I have checked the compression and it is in the 170s all across the board. I power braked the car and pulled one wire off at a time and 1 and 3 were the two that made no difference. The spark is nice and bright. I cleaned the plugs up again and power braked to get it to act up. I then pulled out the plugs and cylinders 1 and 3 didnt even look like they were getting gas. I put a new fuel pump in it also just to rule it out and it did nothing. I also tried a different ecu and even a obd1 ecu with a jumper harness just to rule out the crank sensor and nothing.

 

Air won't cause problems with just two cylinders. If the spark and compression are fine, your only remaining possibilities are the injectors and the timing. If the plugs in one and three end up wet with fuel after running, try replacing the distributor or at least checking the resistance of the three sensors inside. Wet plugs can also occur when fuel atomization is too low because of dirty injectors. If the plugs do not have any fuel on them after running then the injectors are definately not firing properly. In that case, you'd check them with a noid light first and then move on to cleaning, flow testing and/or replacement. Injector problems and distributor sensor problems are the hardest to disgnose so don't feel bad.

 

yea, i have already tested the injector pulse with a noid light and all 4 are nice and bright and pulsing like they should. I also replaced all the injectors with a different set that i know are perfectly fine. After i run it the 2 dead cylinders dont even look like they are getting gas to them. Im about to ship this one down the road, i have been beating my head on this one for over a week now.

 

If the injectors are pulsing and fuel is still not entering the cylinder and you have swapped the injectors to eliminate them as the problem, and pretty much everything else, it only leaves the fuel rail, I would pull the fuel rail and carefully inspect the feeds for cylinders 1 & 3, or just replace it with a known working one.

The above of coarse assumes that spark is not the issue on 1 & 3, [when under load], I assume you have checked that. 94

 

i pulled the rail off and the fuel feed ports are so large it would be impossible for them to get clogged. Just for safe measures i sprayed it with cleaner and blew air through it.

 

OK, you have fuel/pressure at the injectors, [no blockage in rail], you have injector pulse, but no fuel into 1&3, under load.

Do you have injector pulse, [on 1&3] under load?

What is the voltage at injectors 1&3, under load?

Does this car have a injector resistor?

Have you checked harness connections?

I would like to see what the voltage is at the injectors under load, or just do a by-pass, supply 12V+ directly from batt. to injectors 1&3.
I would also want to know what the injector pulse is like under load.

Wouldn't that just burn your button, turns out all that was wrong was a poor connection at the injector resistor or injector power lead junction, or maybe a couple pins in a harness plug between the ECU/ECM and the injectors.

I'm kind of "grasping" here, the above is the only thing I can think of that you have not already done/tried, or maybe you have. 94

 

The injector pulse is nice and bright under a load, just the same as 2, and 4. This is a 99 and im 100% sure of it. I know its a long shot but maybe a torque converter. I know it does not explain the cylinders dropping off but who knows, its my last idea...? Its weird because when i start it up it misses for 1, maybe 2 seconds and just like that, it clears right up like someone hit a button or something. It then idles perfectly fine for about 10, 15 min. then it starts acting up. While its idling fine you can rev it up and it flutters then clears up. If you put it in drive and hit the gas to go the motor just falls right on its face and barley moves.

 

Ship it to me and I'll fix it.

 

what do you all think about the bad torque converter idea?

 

That does not seem like a torque converter problem.

 

how are u testing the injectors? do you smell fuel on the plugs? test the grounds for the injectors via continuity test. any codes? if no codes, it sounds like a problem with either the coil or even the plug wires. did u check the ignition module in the distributor? ur tdc sensor in the dizzy working properly? although u bypassed the crank sensor using an obd1 ecu, it still looks for the tdc sensor in the distributor which would give u a code 9 if bad.

 

I replaced everything inside of the dizzy and i do mean everything. I tested the injector pulse with a noid light and i swapped out all of the injectors with a different set.