ZC Swap Stalling Out

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Hey, I'm new on this forum, and I'm wondering if anyone can throw some ideas my way.

I'm just in the final stages of a ZC swap into a 91 CRX DX. Everything is in there and connected, I've got fuel, air, spark, timing, good compression. Everything seems right. All signs point to "this should work." When I start her up, it runs, and it runs strong. But as soon as the car heats up, and you apply ANY accelerator, it stalls out. Just completely shuts down. And then it won't start up until it cools off. We're all at our wits-end over here and really don't know what to do. We've replaced the injectors three times, the distributor twice.. all kinds of things and really don't know what else to do. To top it off, it seems to be the exact opposite of the problem everyone else has with this engine. All I keep hearing is that everyone else's stalls out consistently when it's cold. At this point, I'd take that. Come tomorrow, this thing will have been in the shop for 4 weeks.

Any ideas, guys?
 
Originally posted by ChaosRX@Jul 13 2005, 03:34 PM
Hey, I'm new on this forum, and I'm wondering if anyone can throw some ideas my way.

I'm just in the final stages of a ZC swap into a 91 CRX DX. Everything is in there and connected, I've got fuel, air, spark, timing, good compression. Everything seems right. All signs point to "this should work." When I start her up, it runs, and it runs strong. But as soon as the car heats up, and you apply ANY accelerator, it stalls out. Just completely shuts down. And then it won't start up until it cools off. We're all at our wits-end over here and really don't know what to do. We've replaced the injectors three times, the distributor twice.. all kinds of things and really don't know what else to do. To top it off, it seems to be the exact opposite of the problem everyone else has with this engine. All I keep hearing is that everyone else's stalls out consistently when it's cold. At this point, I'd take that. Come tomorrow, this thing will have been in the shop for 4 weeks.

Any ideas, guys?
[post=525606]Quoted post[/post]​

something is wrong with the wiring. Check the wiring that you did to go from DPFI to MPFI. Seems like you are starving it for fuel when you hit the pedal.
 
Originally posted by HONDA_F1@Jul 13 2005, 06:35 PM
check ur vacume lines..i had the same problem when i was doing my gf's swap
[post=525716]Quoted post[/post]​

:withstupid: Check your lines. Some ZC motors (mostly ones with automatics), had two "ports" on the back of the intake manifold. Make sure these are plugged up. It could be the tps sensor not wires up correctly, you usually have to switch around a couple of wires on it, although mine didn't work right when I first put in the motor and it still ran ok.
 
vacume lines were the first things checked. as well as all the wiring. these things have been checked about three times each.

people are tellin' me to check the main relay, and i've got a good one comming. hopefully that's it. any other suggestions?
 
Originally posted by ChaosRX@Jul 18 2005, 05:41 PM
vacume lines were the first things checked. as well as all the wiring. these things have been checked about three times each.

people are tellin' me to check the main relay, and i've got a good one comming. hopefully that's it. any other suggestions?
[post=528149]Quoted post[/post]​


Doesn't sound like a relay to me. It starts and runs, so you know the relay is working. Unless for some reason it heats up and stops working, to test that, just short out the switch contacts on it with a peice of wire (not the coil on the relay).
 
yeah, it's starting to look less and less like the relay. recently a fellow who used to work for honda said that we're using the wrong relay. we've got the oem RZ-0063 in there, and they say we need the RZ-0062. I can't find anyone who agrees with that. In the meantime, I've tested the old relay, and found it to be in fine shape. I don't know what to do with this. I'm really at the end of my leash. I'm this [---] close to putting the old engine back in and saying "fuck it."


..oh, and to top it off. i can't find anywhere i can get a 0062.
 
Originally posted by ChaosRX@Jul 20 2005, 11:14 AM
yeah, it's starting to look less and less like the relay.  recently a so-called "expert" said that we're using the wrong relay.  we've got the oem RZ-0063 in there, and they say we need the RZ-0062.  I can't find anyone who agrees with that.  In the meantime, I've tested the old relay, and found it to be in fine shape. I don't know what to do with this.  I'm really at the end of my leash.  I'm this [---] close to putting the old engine back in and saying "fuck it."


..oh, and to top it off. i can't find anywhere i can get a 0062.
[post=528949]Quoted post[/post]​

Ya a relay is a relay, the only difference between one or another is, the current/voltage rating, pickup voltage on the coil and how many pins they have, (ie no, nc). Chances are you could get one from radioshack or a car parts store and replace it, as long as the specs are the same and you know how to wire it.

Try starting it when its cold and heating different sensors and wires up with a hairdryer, see if it stalls. You could use some circuit chiller when the car is warm and do the same, see if it starts, although it would be more expensive. Most computer stores or radioshack sells the chiller in a spray can. That way you could see if its an electrical problem or not.
 
so here's an update with the things we've checked out

we've checked and double-checked...
- vacume lines
- grounds
- resistor box
- ecu
- tps
- dpfi to mpfi wiring
- exhaust
- Main Relay (checked for impedance and solder joints)

we've noticed (in trying to drive it around in a parking lot):
- the car dies upon giving it gas once it's warmed up.
- we are not able to get it to start back up when it's warmed up... with one exception...

it will start back up if we put a hand over the throttle body, forming a seal.

Does this make any sense to anybody?

We're going to look at the IAC motor in the mean time.
 
Originally posted by cheese9988@Jul 20 2005, 11:46 AM
Try starting it when its cold and heating different sensors and wires up with a hairdryer, see if it stalls. You could use some circuit chiller when the car is warm and do the same, see if it starts, although it would be more expensive. Most computer stores or radioshack sells the chiller in a spray can. That way you could see if its an electrical problem or not.
[post=528963]Quoted post[/post]​



That is a REALLY interesting suggestion. Definitely worth looking at. Thanks, cheese.
 
Originally posted by ChaosRX@Jul 20 2005, 12:20 PM
so here's an update with the things we've checked out

we've checked and double-checked...
- vacume lines
- grounds
- resistor box
- ecu
- tps
- dpfi to mpfi wiring
- exhaust
- Main Relay (checked for impedance and solder joints)

we've noticed (in trying to drive it around in a parking lot):
- the car dies upon giving it gas once it's warmed up.
- we are not able to get it to start back up when it's warmed up... with one exception...

it will start back up if we put a hand over the throttle body, forming a seal.

Does this make any sense to anybody?

We're going to look at the IAC motor in the mean time.
[post=528966]Quoted post[/post]​

Are you talking with the intake taken off? If you completely seal it off, it should stall the engine right out, if not you should be able to hear all of the air leaks when you do so.
Also the car doesn't respond to most of its sensors until the motor warms up. Do you have a check engine light?
If you have a manual for your motor, it should tell you how to check the outputs on all the sensors with a volt meter.
 
Did you remember to flip the wires on the tps sensor? If you didn't, unplug it (it will run without it, just with lack of performance) and see if the motor runs.
 
Originally posted by cheese9988@Jul 20 2005, 01:47 PM
Are you talking with the intake taken off? If you completely seal it off, it should stall the engine right out, if not you should be able to hear all of the air leaks when you do so.
Also the car doesn't respond to most of its sensors until the motor warms up. Do you have a check engine light?
If you have a manual for your motor, it should tell you how to check the outputs on all the sensors with a volt meter.
[post=529004]Quoted post[/post]​


yep, that's with the intake off. and, we're not getting any ecu codes. and, unfortunately, i can't seem find a manual for the ZC.
 
Originally posted by ChaosRX+Jul 20 2005, 01:56 PM-->
cheese9988
@Jul 20 2005, 01:47 PM
Are you talking with the intake taken off? If you completely seal it off, it should stall the engine right out, if not you should be able to hear all of the air leaks when you do so.
Also the car doesn't respond to most of its sensors until the motor warms up. Do you have a check engine light?
If you have a manual for your motor, it should tell you how to check the outputs on all the sensors with a volt meter.
[post=529004]Quoted post[/post]​


yep, that's with the intake off. and, we're not getting any ecu codes. and, unfortunately, i can't seem find a manual for the ZC.
[post=529011]Quoted post[/post]​

For the most part you can use a manual for a d16, most of the sensors are the same. I found a manual for the zc online someplace, don't remember, its out there. Did you look at the tps?
 
Originally posted by cheese9988@Jul 20 2005, 01:55 PM
Did you remember to flip the wires on the tps sensor? If you didn't, unplug it (it will run without it, just with lack of performance) and see if the motor runs.
[post=529009]Quoted post[/post]​


I'm sorry just for clarification, what am i looking for it to do if those wires were properly swapped?

oop. nevermind.. i just noticed you have to switch yellow to green, green to yellow. i'll check on that ASAP. (i'm not at the garage at the moment)
 
Ok, so we've checked, swapped and re-swapped the wires on the tps and even replaced it all to no avail.

we're gunna keep lookin' into this on our end, and if anyone's got any other suggestions to throw at us, we'd love to hear em.

thanks for all your help so far.
 
..as of right now, we're going to look into our other lead.. the IACV which I've just heard can be a typical problem on the ZCs...
 
Originally posted by ChaosRX@Jul 21 2005, 02:52 AM
..as of right now, we're going to look into our other lead.. the IACV which I've just heard can be a typical problem on the ZCs...
[post=529347]Quoted post[/post]​

I had to clean mine, which made it run better, but I did that after a year after the swap.
 
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