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Discussion Starter #1
We got the jdm motor installed w/370 injectors, AEM FPR, and Cartech FMU. I can't get a dyno appt. 'til Feb.; theres some race in FL. and then the guy goes to Daytona. I set the v-afc at +10 up to +15 at 3000 rpm all across the board. I for now have the fuel pressure at idle set at @ 20psi and everything runs fine in vacuum. As soon as I get to boost it bogs down, I've tried some different J&S settings so it's not that all the timing is being taken out. I have tried Cartech settings from 40 to 65psi at atmospheric with the rising rate set about in the middle. I was wondering what you have your Cartech set at atmospheric? All that oil blowing through my old motor fried my primary o2 sensor, which my J&S airfuel monitor is tapped into. I replaced the o2 sensor. Any idea on how to check voltages to see if the o2 sensor or the a/f meter are getting juice? TIA
 

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that's great news that you can get the fuel pressure that low with the aem fpr. i assume you're still using the walbro pump?

you are bogging because the vafc is sending the motor a positive map signal. if the car sees more than atmospheric pressure, it will bog, and then eventually throw a code. ZERO out the v-afc. if you still have the JR EMS in place, turn your BTC to about 1/2 way, set your atmospheric to 62.5psi, and put the rise rate in the middle. go for a drive. you'll want the rise rate to be about 4:1, giving you a peak pressure of about 90psi. these are fairly conservative settings, but be careful. if your O2 gauge EVERY shows amber, let up. if you get any signs of detonation, let up.

the o2 sensor outputs between 0 and 1 volt depending on the ratio. just hook a multimeter to the white wire on ecm-d and start the car. you'll see it get pretty rich (like .8 or .9) and then slowly drop.

also, you will probably need to put a restrictor in the vacuum line for the cartech in order to have much control over the rise rate. without the restrictor the screw was nearly falling out in order to get 3.5 or 4:1.

TMontana said:
We got the jdm motor installed w/370 injectors, AEM FPR, and Cartech FMU. I can't get a dyno appt. 'til Feb.; theres some race in FL. and then the guy goes to Daytona. I set the v-afc at +10 up to +15 at 3000 rpm all across the board. I for now have the fuel pressure at idle set at @ 20psi and everything runs fine in vacuum. As soon as I get to boost it bogs down, I've tried some different J&S settings so it's not that all the timing is being taken out. I have tried Cartech settings from 40 to 65psi at atmospheric with the rising rate set about in the middle. I was wondering what you have your Cartech set at atmospheric? All that oil blowing through my old motor fried my primary o2 sensor, which my J&S airfuel monitor is tapped into. I replaced the o2 sensor. Any idea on how to check voltages to see if the o2 sensor or the a/f meter are getting juice? TIA
 

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TMontana, you DID install the Prelude EMS along with everything else, right?

Do you get any CEL's?

You seem to be adding a lot of MAP voltage for someone running 370's. Do you have a fuel pressure gauge to know how the fuel pressure is rising? You can't do **** w/o one.
 

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Discussion Starter #5
Thanks for the replies guys. I have the fuel pres gauge under the hood. I scrapped the JR EMS. I have the fuel system described and the J&S v2.

How do I test my A/F meter?? What is the ECM-D? The primary o2 sensor has four wires, two white, one black(o2 signal) and one gray(o2 reference). My J&S monitor(A/F meter) taps into the gray and black wires. I'm gonna go check the ground now.

Where do I get a vacuum line restrictor???

I'm still at 6psi. We put the aquamist on in prep for 9-10psi and that is coming on @3psi, I should probably turn it off for now. FYI a 3" pulley won't fit on our blower, we're making a bigger pulley to go on the drive pulley where the coupling mechanism is.

I'm gonna run as rich as possible without dumping fuel until I get to the dyno. :eek:
 

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if you don't have the EMS, and your MAP sensor is hooked to a boost source, the ECU is seeing boost. not good. get a check valve or electronic limiter of some sort, or reconnect the EMS. you probably want a pro-active way to retard the timing, rather than just letting the J&S do it when it hears a problem. definitely set the J&S to retard as much as your BTC was.

ECM-D is the connector that goes to the ECU which has the O2 sensor signal on it.

the cartech should have come with a vacuum line restrictor - a tiny piece of white plastic. if you lost it, you can get one from kragen or whatnot but you'll need to drill out the opening to around 1/16" or so in order to allow the cartech to rise at all. then you can use the needle valve to adjust precisely.

TMontana said:
Thanks for the replies guys. I have the fuel pres gauge under the hood. I scrapped the JR EMS. I have the fuel system described and the J&S v2.

How do I test my A/F meter?? What is the ECM-D? The primary o2 sensor has four wires, two white, one black(o2 signal) and one gray(o2 reference). My J&S monitor(A/F meter) taps into the gray and black wires. I'm gonna go check the ground now.

Where do I get a vacuum line restrictor???

I'm still at 6psi. We put the aquamist on in prep for 9-10psi and that is coming on @3psi, I should probably turn it off for now. FYI a 3" pulley won't fit on our blower, we're making a bigger pulley to go on the drive pulley where the coupling mechanism is.

I'm gonna run as rich as possible without dumping fuel until I get to the dyno. :eek:
 

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TMontana said:
Thanks for the replies guys. I have the fuel pres gauge under the hood. I scrapped the JR EMS. I have the fuel system described and the J&S v2.
Why, Tmontana, why?? :confused:
Who gave you the impression that you'd be able to remove the EMS (and told you that everything would work fine)? Are you preparing for a standalone setup of some sort and doing some of the busy work now?

Do you realize that right now, your ECU is receiving positive manifold pressure (assuming you did the JRSC install correctly and connected the MAP sensor to a boost/vacuum source on the S/C adaptor plate)? Do you realize what happens to the ECU when this happens? It freaks out, b/c it isn't programmed to know how much fuel to add under boost. That's your bogging right there.

On top of that, you're adding even MORE pressure using the V-AFC.

You could get around the pressure issue by using the MAP-limiter function of the J&S and by easing off the fuel settings on the V-AFC, but you'd still be plagued by the problem below.

Do you also realize that you're susceptible to part-throttle leaning and/or detonation because you'll still be in Closed loop mode at part-throttle? You won't have that problem with the EMS.

Re-connect the required electronics exactly as described in the manual, then get back to us. If you wanted to emulate schwett's setup exactly, then you might as well have gone all the way and kept the EMS like he did.

The J&S retards only a certain amount of ignition timing across the entire RPM range. The EMS doesn't, it takes most of it from the midrange, and little elsewhere.

TMontana said:
How do I test my A/F meter?? What is the ECM-D? The primary o2 sensor has four wires, two white, one black(o2 signal) and one gray(o2 reference). My J&S monitor(A/F meter) taps into the gray and black wires. I'm gonna go check the ground now.
Edit: Sorry. I completely read past this.
Have you verified this with a JDM helm's?
For reference, on USDM ECU's, it's the SOLID white wire that contains the signal. You'd think that the black wire would be for ground, like on every ECU wire. Oh wait, it is.
Try one of the white wires. If it doesn't bounce back & forth at idle, try the other. (make sure the engine's fully warmed up)
Also, switch the ground wire for the J&S A/F portion into the black wire.

TMontana said:
Where do I get a vacuum line restrictor???
Contact Jim Helbring of Motorvation Motorsports. He sells those for all the Cartech FMU's. (205) 854-8458
(This isn't an advertisement for Jim. I just know he keeps these in stock. You could check with the place that sold you the Cartech unit.)

TMontana said:
I'm still at 6psi. We put the aquamist on in prep for 9-10psi and that is coming on @3psi, I should probably turn it off for now. FYI a 3" pulley won't fit on our blower, we're making a bigger pulley to go on the drive pulley where the coupling mechanism is.
FYI, Jim (from the aforementioned shop) is currently making those for ~$140. If your guy is cheaper, more power to you.

Also, which Cartech FMU did you purchase?

I hope you still kept that EMS somewhere...

Please don't blow another JRSC H22A.
 

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Discussion Starter #8
OOOoooohhh OOOooohhh For The Love of God!

Behind me satan... this car has caused me more pain than any girl or drug ever has...lol...well almost. I'm not trying to be korny, but I can at least Thank The Good Lord for you guys. I get so many different stories. You two have proven the most helpful with us basically trying to do the same thing with our cars. I wish I did have someone's set-up to emulate; all I knew was that Schwett had the 370 injectors. Iranman asked why, I got this car a year and some change ago; I saw JR's advertisement for a 'simple bolt-on' that gave a lot of hp and got it. It has proved anything other than simple. I modded my Harley b4 I sold it, but it was relatively simple stuff no F/I of course. All I wanted to do was get my degrees and keep fighting(box), now I even had to dump my girl for my ride...ain't that some ****

:rolleyes:

back to the point: I need an electronic limiter with a solenoid valve in the vacuum line that goes to the MAP sensor? Is the Apex AVC-R what I need to accomplish this??? I would go stand-alone, but at this point I have all this other gear and I don't want to lose the theft deterrent system and stuff. I'd re-install the JR ems, but would rather not give them the satisfaction, and hold out to sell it.

Concerning the Cartech, you mean I just drill out the white plug on the opposite side from the vacuum line coupling.?

And do I need a voltmeter to test this A/F gauge and would like a little test light work?:confused:
 

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Re: OOOoooohhh OOOooohhh For The Love of God!

the ECU reads the MAP signal (which tells it how much air is going into the engine), the TPS signal (how hard you're pushing your foot on the gas), the IAT signal (how hot that air is,) the ECT signal (how hot the coolant is), and the O2 sensors (how much oxygen is in the exhaust to determine how long to open the injectors for.

now, it doesn't know how big the injectors are. it will ASSUME they are 290cc. since yours are 370, first step is setting the idle pressure to approx 22psi. this will give the same flow as the stock 35psi with 290cc injectors. it sounds like you've done that.

next, you need to prevent the ECU from seeing a MAP signal that would tell it there is boost going on. it will not like that. there are two ways to do this : with a mechanical "check valve" or with an electronic "limiter" that clamps or limits the signal that the MAP sensor sends. the JR EMS contains the latter, as does your J&S (i didn't know that.) make sure that the signal from the MAP sensor is going from the sensor (attached to the throttle body, but with a hose connected to the supercharger) to the J&S to the ECU. the limiter built into the J&S should prevent the ECU from "seeing" boost. you can use the "sensor check" mode of the vafc to take a look at the map voltages. you should never see anything higher than about 2.9 volts. if the signal is already 2.9 volts coming INTO the VAFC, then you have can't use the VAFC to "add" any fuel, so no +15%, +10% or +5%.

because the ECU is not programmed to react to boost, you need another way to give it more fuel when it needs it. the cartech does this for you. boost pressure on the diaphragm causes the return line to close up, which effectively blocks fuel from returning to the tank and increases the fuel pressure at the injectors. the little dial you're turning adjusts the amount of boost that it "bleeds" off into the air, effectively changing the amount by which the fuel pressure goes up as boost is generated. this is the "rising rate." i was surprised to see that i needed about 90psi of fuel at full boost in order to to get a good a/f ratio with the 370s. this is a high pressure but a fairly low rising rate (you set your atmospheric in the low 60s, right?). the bleeder valve can't bleed off that much boost, so you need to restrict the amount of boost coming into the cartech. the little white plastic thing does that for you. stick it in the hose that plugs into the cartech from the supercharger.

you will NOT be able to tune this car (or prevent it from blowing up) without an in-car fuel gauge. get a cheap one from autometer and hook it up ASAP. you have no way of knowing how much fuel that the cartech is adding, especially with the restrictor in there.

the final thing you'll need to control is timing. the JR BTC (part of the EMS you chucked) retards the timing based on the amount of boost it sees. the J&S can do this too, albeit less specifically, as iranman pointed out, but be sure you have set it to do so. i'd recommend, as a safe starting point, 1 degree of retard for each pound of boost. that's a lot, but better save than sorry, right?

finally, the EMS also does a few other things. it sends a very cold (0 degree) IAT signal to the ECU when you're getting on the gas really hard. this makes the ECU provide more fuel. it also artifically deflates the MAP signal when you're off boost, which compensates for the higher fuel pressures caused by the walbro pump. you may end up needing to use the VAFC to lean out the car at NARROW THROTTLE ONLY to do the same.

sorry for the long winded post, but it seems like you keep asking the same questions.


TMontana said:
Behind me satan... this car has caused me more pain than any girl or drug ever has...lol...well almost. I'm not trying to be korny, but I can at least Thank The Good Lord for you guys. I get so many different stories. You two have proven the most helpful with us basically trying to do the same thing with our cars. I wish I did have someone's set-up to emulate; all I knew was that Schwett had the 370 injectors. Iranman asked why, I got this car a year and some change ago; I saw JR's advertisement for a 'simple bolt-on' that gave a lot of hp and got it. It has proved anything other than simple. I modded my Harley b4 I sold it, but it was relatively simple stuff no F/I of course. All I wanted to do was get my degrees and keep fighting(box), now I even had to dump my girl for my ride...ain't that some ****

:rolleyes:

back to the point: I need an electronic limiter with a solenoid valve in the vacuum line that goes to the MAP sensor? Is the Apex AVC-R what I need to accomplish this??? I would go stand-alone, but at this point I have all this other gear and I don't want to lose the theft deterrent system and stuff. I'd re-install the JR ems, but would rather not give them the satisfaction, and hold out to sell it.

Concerning the Cartech, you mean I just drill out the white plug on the opposite side from the vacuum line coupling.?

And do I need a voltmeter to test this A/F gauge and would like a little test light work?:confused:
 

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Re: Re: OOOoooohhh OOOooohhh For The Love of God!

schwett said:

now, it doesn't know how big the injectors are. it will ASSUME they are 290cc. since yours are 370, first step is setting the idle pressure to approx 22psi. this will give the same flow as the stock 35psi with 290cc injectors. it sounds like you've done that.


I'm curious why you said he needs to get his fuel pressure so low if he is using the VAFC. Are you saying that if he get's his FP that low he won't need to dial in any correction on the VAFC?
 

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Re: Re: Re: OOOoooohhh OOOooohhh For The Love of God!

it's much better to get the pressure where it's supposed to be and then use the vafc to "trim it out." you can guarrantee that a 1ms pulse at 35psi with a 290cc injector is the same amount of fuel as a 1ms pulse at 22psi with a 370cc injector. you can't guarrantew how much fuel your getting at 35psi with a 370cc injector and a MAP signal that's artifically adjusted to "30%" lower than it really is... does the ECU really have tables for 700+mm of vacuum? is this relative adjustment correct at every RPM? etc etc etc.

finally, there seem to be times when the VAFC or MAP mod correction isn't effective; it has been suggested that the out of gear / clutch down near stalling that occurs is because the ecu gives a little squirt of fuel right before it hits idle (since the injectors are shut down on the way down from xxxx rpm) that does not seem to be "corrected" by any of the VAFC points or the JR MAP converter. this is unverified, but it's always better to *not* have to "fool" the ECU.

those of us with the MAP converter still installed would not want to go to a "stock" fuel pressure - you'd want to go to the 370cc equivalent flow for the pressure that the JR kit is designed around, which is 52psi idle, or 32psi with 370s.

LuderSH said:


I'm curious why you said he needs to get his fuel pressure so low if he is using the VAFC. Are you saying that if he get's his FP that low he won't need to dial in any correction on the VAFC?
 

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I've been planning my install of the 370's around not needing to get the VAFC. So in order to get the idle pressure low enough all I have to do is replace the sock FPR with the AEM adjustable one correct? In addition to the Cartech of course. Also on AEM's site it says that their FPR only works on the Prelude if you have the AEM fuel rail. Can anyone verify?

thanks
 

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that's the best way - aem fuel rail plus aem fpr. beware of the aem and high pressures, i have seen several accounts of it leaking past 100psi.

there are two other ways to go, both ghetto. drill a hole in the stock FPR to lower the pressures across the board, or cobble together a bunch of fittings to allow some fuel to BYPASS the stock fpr. i drilled the hole and my pressure went down to about 35psi; i don't think i'll really be able to get it lower without making too big of a hole.

LuderSH said:
I've been planning my install of the 370's around not needing to get the VAFC. So in order to get the idle pressure low enough all I have to do is replace the sock FPR with the AEM adjustable one correct? In addition to the Cartech of course. Also on AEM's site it says that their FPR only works on the Prelude if you have the AEM fuel rail. Can anyone verify?

thanks
 

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Discussion Starter #17
Anyone putting the AEM fpr on w/the JRSC. You have to take it apart not only to change the outlet fitting, but then to turn the vacuum hose fitting around to the same side of the fuel rail. Otherwise it looks as if it would hit the SC belt.
 

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could you do us a favor and take a picture of it installed? i think you are the only one so far with the jrsc + aem rail&fpr.

TMontana said:
Anyone putting the AEM fpr on w/the JRSC. You have to take it apart not only to change the outlet fitting, but then to turn the vacuum hose fitting around to the same side of the fuel rail. Otherwise it looks as if it would hit the SC belt.
 

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Discussion Starter #19
Alright definitely, for you all helping me out I can at least take some pics this weekend. I can scan them and send them aol, i just can't fit learning to post links and stuff into then learning curve right now...:mad: that is the look on my face from the PAIN...lol LSAT's on the 9th; haven't even really had time to study. a/f gauge o2 sensor getting to me...,.
 
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