1990 Honda CRX Loss of power

Tiny
1990HONDACRX
  • MEMBER
  • 1990 HONDA CRX
  • 4 CYL
  • FWD
  • MANUAL
  • 200,000 MILES
I recently did a dpfi to mpfi, I changed the wiring over, put in a pm6 ecu, a crx si intake with fuel injection, resistor box. The ecu throws no codes.

It idels at 1k and is smooth through the rpm range up to 7.5k If being driven and I mash down on it it runs smooth, no signs of missing or backfires. At high rpm and shifting gears it jerks and seems to loose power for a few seconds and then catches back up.

It has new wires, new cap rotor, new distributor, new plugs, and a new timing belt. I ran a bottle of injector cleaner through the gas thinking it was a clog in the injectors but no result change.

I was leaning towards its off time by a mark or so but im not sure. The distributor is ajusted to be at the highest point so it idles a little higher then if I were to push it back to its lowest point and get a idle of around 800

any ideas. IT would be most appreciated
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Thursday, March 19th, 2009 AT 2:18 PM

13 Replies

Tiny
KHLOW2008
  • EXPERT
Hi 1990hondacrx,

I would suggest getting a timing light to check the ignition timing. If you are able to get the correct ignition timing with the distributor holding bolts somewhere in between the slots, then there is no problem with the timing belt marks.

However if you are not able to get the correct timing, either the distributor is not the correct one or the timing belt is off.

For fuel injection vehicles twisting the distributor around is not going to help as the ECM would be monitoring the advance and retards of the timing.

Correct idling speed should be 700 rpm.
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Friday, March 20th, 2009 AT 11:12 AM
Tiny
1990HONDACRX
  • MEMBER
The timing is correct to the specs provided by honda. I cleaned the EACV valve and tried doing some idle ajustments, but even with it all the way out it still has a idle of around 1200 rpms.

Is their any other reason why I would loose power when shifting to a lower gear at a higher Rpm?

It bogs down only when im downshiffting while trying to race.

If im going up in gears its usually allright and it will stay in motion without heassitation as long as the rpms are pretty much kept high.

I only used the ajustments on the distributor to keep it at a high idle. The car runs worse if I kick it back all the way and its at a lower idle.

Still no check engine lights.

Went through all my wiring and it still shows the same symptoms.

With changing to fuel injection would there be the need to advance or retard the timing?

Any ideas on what is causing the power loss in only certain situations?

Everyting seems to be correct, the distributor is correct for my application. It was all matched up to obtain a proper conversion and you can rule out a improper part being used. Would a bad connection to the fuel injectors be the reason since I had to run to connecters directly to the ecu? I used proper gauged wires but didnt soulder and heat shrink.

Its a problem only in a certain senrio witch leads me to think its not a sensor or something that was added.

It is running a full exaust of 2.5 inches off a 4-2-1 header so back pressure is minnimum due to a race cat that is high flow.

It sounds like mabye a little bit of back firing through the exhaust but its only when letting off the gas. A rumbling like sound of diffrent pitches.

Trying to give you as much info as I can.
Car drives well under non stress conditions and only seems to be a random problem. Im so confused, and not sure what next to check, went through everything if anyone has a idea please throw it out there

Thank you
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Sunday, March 22nd, 2009 AT 6:58 PM
Tiny
KHLOW2008
  • EXPERT
Idling speed should be 700 and if you are not able to get it down even with the idle adjust screw fully turned in, then there is a vacumn leanake somewhere.

If the throttle plate stopper screw had been adjusted, it would allow too much air to pass through and cause the high idling rpm.

This would also affect the TPS setting in relation to throttle opening and air passage.

The bogging down at high rpm could be due to insufficient fuel being delivered to the injectors and that could be due to partially clogged fuel filter.
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Monday, March 23rd, 2009 AT 1:08 AM
Tiny
1990HONDACRX
  • MEMBER
I dont see how the fuel filter would cause the bogging down to occur only when it is being shifted down, there is no problem when going through the gears shifting up and at a stand still in nutreal I can reach max rpms with no segnificant probelem.

On the thought of changing the car to fuel injection, do you know if the crx si had a higher timing set then the base model crx? It has the timing on the car and is ajusted to the base model specs.

Ill try ajusting the throttle screw today and see if I can change the idle. Ill put the dizzy in the middle and work from there to try and get a idle of 700.

I have 1 line that runs from the center of my intake to the engine head that has a good vaccume hold but its almost like its hooked up to re-ciculate engine gasses. Pvc valve type set up but has no ball or anything to stop circulation at any point.

If the dizzy was ajusted up to far would that cause a hessitation when downshifting to obtain a higher rpm.
But not if you work your way up to the higher rpms in the motion of 1st 2nd 3rd 4th 5th.

Im not trying to be rude with my replys I just dont want to cause any confusion on what is happining.
Thank you for your ideas so far, I can use what ever help possible
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Monday, March 23rd, 2009 AT 4:00 PM
Tiny
KHLOW2008
  • EXPERT
When accelerating the engine is under strain so there is insufficient time for fuel starvation to set in. When down shifting, engine rpm shoots up quickly so a minor clogging would be noticeable.

When ignition timing is too advanced, it would have a good low end acceleration but when it nears the max power rpm range, it would tend to hesitate/pull back. Downshifting at high speed would require high rpm.

Ignition timing should be set only at the correct idling speed. A higher idling speed would have a more advanced igntioon timing so if the idling speed is incorrect, you would not get the correct ignition timing.


http://www.2carpros.com/forum/automotive_pictures/192750_IgnitionTiming90Honda_1.jpg



PCV should have minimal vacumn feel and there is a spring loaded check ball inside. If covering up the PCV reduces the idling speed to minimal, then it is faulty and should be replaced.

No worries about any comments. If you think we have made a wrong judgement, please let us know. To err is human and sometimes we might have read or interpreted the question wrongly. At times we might not have expressed ourselves clearly so any pointers are always welcomed.
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Tuesday, March 24th, 2009 AT 9:46 AM
Tiny
1990HONDACRX
  • MEMBER
Thank you for the more indepth insight on the fuel filter, I belive the throttle isnt ajusted on the intake by a screw like most vehicles and is done with vaccumes, the only ajustment I found was on the EACV and it will only raise the idle and not lower it because it is allready pulled back, I re-traced all lines and are functional, im going to try the fuel filter and look for a change

The pvc is good still and has a line running to it that if disconencted almost kills the engine?

Is that good or bad? It runs from the top of the pvc to the intake manifold, ill upload some photos for refrence.
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Tuesday, March 24th, 2009 AT 10:37 AM
Tiny
1990HONDACRX
  • MEMBER
Here are photos of the vaccume lines that run from the pvc to a sensor then down to the intake manifold.

(picture 3)

also is a photo of the EACV wich is ajusted to the lowest idle for cold conditions I belive is what its for.

(picture 4)

the one that shows the front of the intake is the middle hose that runs down under the manifold into a box, it has a signifact purpose wich I dont know what it is because without it attathed to the manifold the engine would run excessively high
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Tuesday, March 24th, 2009 AT 11:04 AM
Tiny
KHLOW2008
  • EXPERT
The red circled hose is for the MAP sensor ( red circled Black item )
The white circle is the purge solenoid and it should be getting vacumn from the maniflod, the blue hose that you have on the manifold.

The green circle has the idle adjust screw.


http://www.2carpros.com/forum/automotive_pictures/192750_a90Civic1_3.jpg



The 2 hoses are coolant hoses which I dont see any clips and are loose, guess you did not connect them correctly. Without coolant passing through the EACV, the idling speed would be high and inconsistent.
The EACV is factory set and should not be adjusted. It could cause irregular idling and idling speed fluctuation when AC is turned on and off.


http://www.2carpros.com/forum/automotive_pictures/192750_a90Civic2_2.jpg

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Tuesday, March 24th, 2009 AT 12:25 PM
Tiny
1990HONDACRX
  • MEMBER
No ac in the car anymore, was pulled out when I bought it, and no coolant flows through the lines, they seem to be just in a circular path, possible coolant bloackage mabye.

The blue line runs from my Fuel pressure regulator to the intake manifold, should they be connet in a t patter like these lines are and the map sensor should be seperate running only to the manifold?

Purge selenoid should run to the manifold-

Map sensor should run to the manifold-

EACV should recieve coolant from engine-

(took cap off EACV and there isnt any hole for coolant to reach internal sensor, just seems like a circular route.)

Will look for idle screw again and see if I can find it,
and re run hoses like explained.

Will update as soon as I run through the parts and check to see if re-routing helps. Thank you for more insight, I owe you big time,

Are you a certified Tech?
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Tuesday, March 24th, 2009 AT 7:08 PM
Tiny
1990HONDACRX
  • MEMBER
Found the idle screw. It was ajusted all the way out, and i turned it in completely. Idle's around 775-800 now. Taking it to work today, 200 miles round trip.

Didn't adjust the vacumes yet but if its no better now then ill go there next. Is it important to have fluid in the eacv if there is no ac? Hoses seem to run together in a circle from bottom to top with no point to meet any coolant lines, ac was completely removed before i purchased the vehicle.

Great info!!


http://www.2carpros.com/forum/automotive_pictures/333708_100_0578_1.jpg



Above is full shot


http://www.2carpros.com/forum/automotive_pictures/333708_th_fenders_1.jpg



Here is the full car photo of whats been my project for the last 6 months, purchased for 350$, invesyed 700$
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Wednesday, March 25th, 2009 AT 4:46 AM
Tiny
KHLOW2008
  • EXPERT
Without coolant passing through the EACV, the idling speed might act a little weird when engine is warming up. There should be joints for the hoses on the thermostat housing and water pump passage under the manifold, unless the parts were replaced without those.

The MAP sensor vacumn should be isolated from others as the vacumn port is specifically for it and any disruption in the vacumn would cause the MAP sensor to provide incorrect signals to the ECM.

Instead of the fuel regulator vacumn hose, use the other Black hose with a T connector, which is connected to a dash port vacumn.

I am not a certified Tech as I do not reside in the US. I do have a diploma in Automotive engineering and have worked with Honda vehicles since 1982.
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Wednesday, March 25th, 2009 AT 10:03 AM
Tiny
1990HONDACRX
  • MEMBER
Isolated the map sensor when I got home and tweaked the idle just a little bit more, car runs perfect and very resposive going up in gears! Seemed to gain a 1/4 of a second in 0-60!

Still a hesitation problem today getting onto a highway and needed to get infront of a semi-truck.

Car lost power when letting off gas completely and re appling gas no gear change. Seemed to be like fuel shut off and then returned. Very weird.

Re routed the PVC and the FITV to be correct.
No knobs or access points for Coolant to pass through the EACV. Didn't remove any lines from the water pump area and cant locate any replaced lines.

Could the coolant that passes through the intake manifod and back to the block be used to run through the EACV and not cause problems if I added lines to make it work?

Car seems to be okay now havent taken it out to see if the hesitation has been resolved, ran a bottle of fuel cleaner and octane booster to see if it was a possible clog.

If I unplug the map sensor how its hooked up now engine will die completely. Seems to be working great in that area.

What should I run the blue hose to? What dash port vaccume?
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Wednesday, March 25th, 2009 AT 4:14 PM
Tiny
KHLOW2008
  • EXPERT
Leave the blue hose alone. The purge solenoid can be attached to the black hose via a T joint. That hose is presently attached to a dashpot actuator which for some are used as AC idle up control.

If you do not have any problem with erratic idling, then the EACV can be utilised without the coolant hoses. If you do not have any coolant joints at the thermostat housing, it would be difficult to get the correct position. Just running 2 coolant hoses is not going to work. It must complete a circuit that has pressure to push the coolant or suction from the water pump to ensure the coolant in it is moving all the time.

Hesitation when accelerating after deceleration.
Which of the following is happening?
1. Loss of power as if it is missing a beat.
2. No response from the throttle momentarily?
3. Engine seems to be under powered? Like you are in too high a gear.
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Thursday, March 26th, 2009 AT 7:48 AM

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