I picked it up this weekend and found a few things that concerned me. First, the car idles a little high (about 1200) and the tach is a little jumpy. Second, it has a miss or sort of a stumble at times. It runs and sounds very well other than that. Any info on the problem and fix would be great. Thanks in advance.

 

it could be a vacuum line popped off or split you should replace all the vacuum lines with silicon hoses

 

Check the MAP sensor and also, what is the compression on the motor?

MAP sensor is located on the firewall right behind the throttle body Just make sure that it is hooked up.

If you don't know the compression I would get it checked just for the knowledge that you are in good starting shape.

 

YOu should perform the full 60k service on the car to know where you stand -- this will include changing all fluids and filters, plugs, plug wires. What are your vacuum values at idle?

 

I did find one vacuum line off, it was at the rear of the intake m.f. It looks like it was connected to something looking similar to a fuel regulator. Well, I reconnected that vacuum line and then at every stop the engine would die. So I have disconnected it again. Well, after putting around town today getting insurance, tags and title and running a few errands , the drivability has gotten worse. It's bucking alot at low speeds(40 mph), and I dare not drive fast. I have parked it until I find out what the deal is. Has anyone experienced this?

 

you should download a diagram of the vacuum lines so you know where everything goes, if you cant find one i could e-mail it to you

 

Well, I ordered a repair manual a week ago, the diagram should be in there, right? I'm not one to refuse help or info right now, so send it to me... hdp501@aol.com But I really do need to know if it is indeed a vacuum problem or do I have worse issues than I suspect.

 

Idle... may be just set too high on the linkage side of things by the intake manifold. Try to slow it down there first.

Then another thing you have to do... a fresh set of plugs (every year) on this car (FD) does more for the car than anything I know. Try it.

On the less rewarding things that you have to take care of is a new fuel filter.

Congratulations,
DI

 

If the idle is high and bouncy, the TPS (throttle position sensor) is probably just out of adjustment. This is very common. It can cause the idle to "hunt" or bounce, and it can also cause the throttle response to do strange things at partial throttle. There is a proceedure in the manual to adjust it. However, if you are still having problems at WOT, you have other issues.

FYI- These cars commonly have what is know as a 3000 rpm hesitation. Almost all FD's with a stock ECU have it to some degree. Some are mild, others will just about throw you through the windsheild. This could also be your problem (maybe).

Jeff

 

hahaha, so true. my hesitation was so bad it made my car basically undrivable.

you can try unhooking your O2 sensor. if it helps, it is most likely the 3k rpm hesitation. there are about 20 different "fixes" for this problem. it seems that no one particular fix cures every car.

 

Alot of mention about vacuum line problems without anything about a boost guage. I would suggest hooking one of these up before you go into looking all over for hose placement. Even if you dont want to buy one now ( you mine as well as you will deffinately need it down the road) you could just borrow one from a friend or have a shop hook up a pressure guage... If you have good vacuum at idle ( -16 - -18 in/hg is the good range I believe) and throughout your WOT Rpm range then I would look into plugs or fuel filter... Just my $.02.
Good Luck,
Catlin M

P.s. Its a shame new owners get these types of cars... this is exactly why our cars have such bad reps... I wish you the best of luck man and dont let this first impression change your view of the FD.

Edit: could you possibly post a pic of the hose that was disconnected then caused more problems when reconnected?

 

ISC solenoid(idle speed control). Also what hose are you talking about that you found popped off, gotta pic of it or can you get one?

 

I will look to see if I can find a pic of it on a website some place.

 

Been looking off and on all morning for a pic of what I'm talking about... I guess I need to buy a digital camera. But anyway, all I know is it's on the lower backside of the intake m.f. next to the firewall. The thing the vacuum hose was connected to looks sort of like this...

 

Anyone know?

 

I know what you are talking about. I am not sure what Mazda calls that little canister, but the vacuume hose should definately be on it. If it is off, the car has a vacuume leak, which could be causing your car to run poorly. For now, try plugging that hose off and see how the car runs.

It sounds like somebody has messed with the throttle body linkage and lowered the idle too low. There is a proceedure for adjusting the idle, but it uses a bleed screw on the bottom of the throttle body, NOT THE LINKAGE ON THE THROTTLE BODY (despite what some others might suggest). The little canister in question is connected to that linkage, so if the car dies at a stop light, leave it unhooked for now until you get your shop manual and adjust the idle properly.

Good luck.

Jeff

 

That's what I meant. The simple/obvious stuff first.

DI

 

Found this online, sweet, pic of all the vacume lines with color. I have a print in B&W, this is **** since you can kinda trace where things are. Sure the web site owner won't mide me posting.

http://www.rx7guru.com/

So from that, here is the pic-





Hope that helps, should be something close to get your mouth wet and figure where your vacume leak is. From experience, you usually get a high idle when a vacume leak occurs, the rest is usually someone adjusting the (which you shouldn't do) throttle body to compensate for not being able to find the leak. There are literally tons of lines on these things, just one pinch or leak or bad check valve (don't forget backwards check valve!!) will cause everything to go into dissaray. Be careful, it can also cause the detonation of death, stay off the throttle until you get it pinned down.

 

Thanks guys. Now I just wish my hoses were color-coded

 

Don,

in the pic that you found that's similar, just so everyone knows, thats at the front side of the car, close to the intake/radiator area.

As far as the bucking, try the extra ground strap from the negative terminal to the frame, and clean the other contact areas of the other ground wires (one on the firewall to UIM, bottom spark plug side is another ground strap). Cheap maintainence.

using the colored wiring diagram, which one doe sit appear to be on the back side of the engine?

Tim

 

Hey Tim.

It apears to be in the area of the Air Control Valve and Pressure Regulator. It's below and to the right of the firewall grounding strap (facing the engine).

 

I just got my repair manual in the mail and found the Symptom Troubleshooting section (K). On page K-181 # 27-30 describes exactly what my car is doing.

 

Well? Fill us in lets see who knows their stuff . I am interested in what it was/is depending on wether or not you fixed it...
Thanks
Catlin

 

I won't get to work on it till this weekend. I hope to change the air and fuel filter as well. It had an oil change the day before I picked it up and a new radiator a few months ago.

 

I couldn't think of the name at the time I posted last time, but I thought you were describing the double throttle control actuator. This is responsible for allowing the secondary plates to open up on the TB once the car gets warmed up. If the green hose in the drawing above is not connected to the actuator, you will only get marginal power, even when the car is warm.

Let us know what you find.

Jeff