Alright, let me please tell you what I have, and then maybe someone can help me out. I have just recently aquired a 1989 Honda CRX Si, with an already existing D16Z6 swap and GRreddy turbo kit I assumed designed for that motor (92-95 Civic). Unfortunately whoever had done the work left it a bit unfinished as it's still using the OBD0 wire configuration and an OBD0 distributor (no vtec connected). I do plan on rewiring for OBD1 soon, as I have a new ECU and am looking for an inexpensive harness converter. JDMshit has one for $110 shipped I may get.

My dilemma:

When I 1st aquired the car, it ran great. Gated at around 8psi and seemed to hold up well. :evillol: However, recently it's been acting a little strange, well, downright annoying. :mad: In the past, when I would mash the accelerator down, I'd have instant gratification starting in a low RPM range, hearing the familiar spooling and the burst of power, and the awesome "psssssht" of the BOV on accelerator let-up. Well, now, more recently, it's a HUGE change, instead of launching forward as I step on the gas, I hear the spooling of the turbo, but instead of the launch forward I come to love, it feels like a huge hesitation. Almost a pulling sensation until it reaches a high RPM, then with a whipping of the head back it finally bursts into power. :mad:

Ok, now, what's wrong? Why the hesitation? People suggest whether it may be filthy injectors, a boost leak, or maybe the timing's slipped? I'm not sure. Perhaps someone has some suggestions? Please, ask any questions that may help? Regarding boost leak issues, I've checked all connections to make sure they're tight, and they are (fitting around all joints and sections). Should I check anything else? Someone on homemadeturbo.com suggested perhaps my internal wastegate's actuator could be sticking in the open position at 1st then slapping shut, which could explain the sudden burst of power. Any ideas?

Help? :confused: :banghead:

my guess is the wastegate. have a friend watch the arm to see if it moves as you go through the rpm range

I agree wastegate.
Does the BOV still sound when you let off the gas, after the car gets it's sudden boost of power?
Also you are not running a Boost gauge? I would reccomend getting one.

Also tell us some more about the kit, what kind of fuel management do you have etc.

Ok, yes I do have a boost gauge. It still seems to boost up to about 8psi like it did before, so that part seems fine. And no matter where I let off the gas, the BOV still sounds, whether I have the hesitation or not.

When I got the car, I was told it was GReddy kit adapted from the 92-95 Civics to fit the CRX, as the car does have the D16Z6 swap. I have had the car just a couple weeks and haven't had time to tinker around on it to check anything other than the joints, to make sure they were tight and all that stuff. I am going to verify that tomorrow since ppl say "GReddy" will be stamped somewhere on the turbo. Regardless, it does have an internal wastegate. It's also using a DSM side mount intercooler (nice and concealed compared to a FMIC), and Paxton FMU.

does that a boost/vac gauge? hows the vac readings? do you have an fuel pressure gauge? hows your gas mileage? spark plug color? any other electronic accessories? timing set at? Do you have a cheap AF gauge, if so, hows the light show looking? the cars been boosting 8psi with what fuel management and how long? cracks or leaks anywhere along the path of the exhaust?

Wow, Superblue, lotsa questions, and that's good. Thanks!

Well, let's see here:

It had a piece of crap A/F gauge, ripped it out. ANNOYING! So no A/F. (crappy LED one)

Boost Gauge reads about 8 psi and has been doing so since I've had it. The "dilemma" however is more recent.

Mileage? HA! I noticed it eats gas like a mofo, alot more than my SOHC ZC did with the stock fuel management in my other CRX. I know she runs pretty rich, exhaust is a little thick(er). But that's been like that since I've had it too.

Leaks or cracks? Haven't noticed any leaks or cracks.

Fuel pressure gauge? No, sorry. Stock fuel pump but with that Paxton FMU.

Someone on the homemadeturbo forums mentioned something about the TPS. Well, the TPS isn't there (snapped off it like a twig) which was also an already-existing issue far prior to the issue I am having now. However, will the TPS missing develope any issues in the longrun? it seems to ahve ran fine without it, I have another TB that has this on it, I'll just swap TBs.

People have been mentioning the wastegate perhaps sticking open, then slapping shut when it senses set boost, thus the surge of immense head-whipping power. Whatcha think?

It had a piece of crap A/F gauge, ripped it out. ANNOYING! So no A/F. (crappy LED one

though not very accurate, it however, does a good job at telling you your o2 sensor is gone.

Boost Gauge reads about 8 psi and has been doing so since I've had it. The "dilemma" however is more recent.

a good vac gauge will help aid you to locate possible vacuum leaks and busted ringlands. i think everyone who buys a boost gauge should get it with the vac reading also.

Mileage? HA! I noticed it eats gas like a mofo, alot more than my SOHC ZC did with the stock fuel management in my other CRX. I know she runs pretty rich, exhaust is a little thick(er). But that's been like that since I've had it too.

Fuel pressure gauge? No, sorry. Stock fuel pump but with that Paxton FMU.

a fuel pressure gauge will make idle and static pressure readings much easier. will give you a better assessment of how rich you are running which will be helpful in linking it to other possible fuel system problems. a bad o2 sensor and running rich will definately cause bogging.

Someone on the homemadeturbo forums mentioned something about the TPS. Well, the TPS isn't there (snapped off it like a twig) which was also an already-existing issue far prior to the issue I am having now. However, will the TPS missing develope any issues in the longrun? it seems to ahve ran fine without it, I have another TB that has this on it, I'll just swap TBs.

a broken throttle position sensor (tps) will create uncontrolled delivery of fuel because the pcm will think the throttle is moving. the pcm figures how much fuel will be delivered according to the throttle valve angle, which is observed by the tps. why dont you just switch the TPS instead of the TBs?

People have been mentioning the wastegate perhaps sticking open, then slapping shut when it senses set boost, thus the surge of immense head-whipping power. Whatcha think?

as the boost gets closer to the boost setting of the spring in the wastegate, the spring will start to actuate causing the wastegate to open. getting to full boost with the turbo takes longer with this condition. if you dont have a boost controller already, go get one.

Leaks or cracks? Haven't noticed any leaks or cracks.

did you actually give it a detailed closeup visual of leaks from the manifold to the downpipe?

are you using all the original parts from the greddy kit?

Well, I took it to a shop, the O2 Sensor I guess is reading normally.

Hey, you said something about a boost gauge reading vacuum as well. What does it look like? Is it one of those gauges that read numbers backwards? If it is, I have one of those hooked up already. That's my primary gauge.

As for all the parts, since it's a D series Vtec in a CRX, the only differences are the charge pipes right before the main one that goes to the TB, and from what I understand, all the rest is the same.

As for changing the TB, it's easier than taking it off, shaving off the rest of the TPS, since on this TB, they seem riveted because of the preset on the TPS, and I have another complete, unharmed TB identical to it. A few bolts and Viola! Changed! (except for the gasket I ordered from Honda, which I will get in a few days)

As for leaks and cracks, I did do a visual inspection and things seem fine. I will check about those ringland issues though when James down at Garage 808 close by me, in Eugene, Oregon gets back from X-Mas vacation. He's the turbo guru around the area, focusing on turbo and na setups at his shop. While he's been done is why I've been asking questions left and right. I do appreciate all your help though. It gives a lot to think about and check out! :)

Oh, and that wastegate issue. People were saying that since it's an internal one with an outside vacuum actuator, perhaps the actuator is sticking? I dunno. Help? haha

check for a clogged cat. also, do you have a boost controller? if not, get one.

wel i don't know a hole lot about turbo crx's but i do about dsm turbo. and it sounds like a wastgate prob, or a vac, i would change that fuil pump asap, and ck the injectors the mitsu 450 should be fine i have seen them on ebay for like 10 to 15$ so do that. you need to ch the o2's also sounds like that are out. if it is the cat (take it off) you should go 2.5 to 3.0 on the pipes. my mitsu used to drop realy hard when i would get to 6,000 rpm and i had it dynoed and it should it was my acshuwyter ( can't spl it ) but if you have one ck that. i am pretty sure that it is the wasgate and you will have to replace it. i have one from a blown t25 and i have like 2 ex side's if you need them. you are now gonna learn that turbo's if not done right are a pain in the (_Y_). hope i helped a little.:thumbsup:

The pipes and cat are all newer. 2.75 from the downpipe on back with a high flow cat. The O2s checked fine. My attention is focusing on that wastegate for right now since that's what everyone's saying, and once I know if it's that or not, then I'll proceed. Thanks for all the help!

have u cheacked the vacum line runnin to the bov and wastegate and all that shit

have u cheacked the vacum line runnin to the bov and wastegate and all that shit


Yes I have checked all that. I don't get what it may be. However someone told me to get a vacuum/boost gauge. And my question to that was: is that a gauge that reads positive above 0 for boost, and negative of the 0 for vacuum? If it is, I already have it, and how do I read for vacuum? (boost reading is a given).

hhmmm, it might not even be the turbo kit since everything appears to be working well. heres an unobvious shot, check ur clutch, might be going bad. wish i can better assist u, but everyone else pointed out the obvious problems

you can use the vacuum gauge as a cheap diagnostic tool. it can be used to check for worn cylinder walls and rings, leaks at the head, leaks around the intake mani, clogged exhaust system, valve problems, ignition problems etc,etc,etc. It serves as a gauge to pinpoint and narrow problems, not to locate exactly. Different vacuum leaks and pressures create different readings.

A vacuum gauge reading should be steady between 17-22 inhg at idle (give or take 3 inhg). I dont really feel like writing a whole topic on it. maybe someday, but, anyways, if your idle is not as described above, then you have problems somewhere. if you have problems with your vacuum readings, then give a detailed explanation of your vacuum gauge readings from type of needle movement on the gauge, speed of movement(ex. needle dropping or rising steadily or slowly with large or small fluctuations at a certain reading, rapid vibrations, strange random drops in pressure, etc,etc,etc).

Anyways, hope i answered your vacuum gauge question.

Well, I did something yesterday and perhaps MAYBE it worked. However I didn't notice immediate results in regards to the solution to my draggy feeling when I would mash on the accelerator, but perhaps it was just taking the ECU a little while to get used to having it fixed, but I went ahead and swapped throttle body's as I was suggesting since the TPS was busted on the other one. As I said, at 1st, when I took it for a test run immediatley after swapping them, it seemed to have lagged just as bad, and I was getting a little discouraged, but after having the car run for a while, it seemed to have perhaps fixed the issue.

Now I am thinking that after a LONG while, not having a TPS was screwing things up over a period of time. I know that thing was broke for about a few good months before I noticed the draggy feeling, cuz the draggy feeling wasn't something that was "progessive" but something that seemed to pop up all of a sudden, and haunt me since then, but since I've swapped those bodies yesterday, things seemed to have evened out a bit, I'm not noticing the feeling as much if at all anymore.

What do you guys all think? Could it be masking a serious issue?

Oh, one other thing however, I DID notice that the throttle body that I HAD on there had this tube out the top near the MAP sensor, on the opening side that stuck up, and I wondered where it led to into the body, and I found these really small holes just before the throttle plate that it channeled to. What is this for? The "new" throttle body I am using now doesn't have that, and the other one had a hose going to this little canister thing, which is just dangling there not being used now that I've swapped the bodies. I notice from this canister, some vacuum lines running to these small things attached to the firewall... I'm confused. What are those for? Emissions? Cuz it's not affecting the way the car runs... Do I need them? I live in Oregon, it's not like CA where that stuff is super important... Lemme know if I can scrap that stuff?

BUMP! Anyone know?

he would most definitly notice his clutch not gripping.. and being turbo'd i would hope he's not running on a stock clutch. this does sound a lot like the wastegate is sticking open, and suddenly closing thus the jolt in boost/power. I'd say take the turbo out and inspect everything, and apply some lube to all the moving parts. check for wastegate play, and do an inspection of all the seals you can get at.

No, not a stock clutch, it's an ACT Stage 2. And the strange thing is that I've inspected most everything but that wastegate... Ugggh! Need a dyno!

Oh, one other thing however, I DID notice that the throttle body that I HAD on there had this tube out the top near the MAP sensor, on the opening side that stuck up, and I wondered where it led to into the body, and I found these really small holes just before the throttle plate that it channeled to. What is this for? The "new" throttle body I am using now doesn't have that, and the other one had a hose going to this little canister thing, which is just dangling there not being used now that I've swapped the bodies. I notice from this canister, some vacuum lines running to these small things attached to the firewall... I'm confused. What are those for? Emissions? Cuz it's not affecting the way the car runs... Do I need them? I live in Oregon, it's not like CA where that stuff is super important... Lemme know if I can scrap that stuff?

snap a pix. it'll be easier.