I recently had a person repair my AC evaporator and my car runs horribly now, when the ac is on the car will shake pretty badly, like you can feel it in the steering wheel and through out the entire car. He claimed he put and American made AC evaporator in the car and I'm not sure if putting in the wrong evaporator would do anything. Any comments?

 

Does the A/C work well? Is it just the electrical and acces(belt) loads that are put on the engine when the air is switched on? I guessing it didn't do this before, correct?. I have a evaporator here from a car I took the A/C out of if you would like it.( probably cheap, gotta talk to the customer)PM me if you like. It worked well before removal.....The car would run a little bit rough when the air was switched on.(rpm's drop and shakes) Even stalled every now and then.

 

how bad was the shaking? why does like the AC seem to like kill the car so much? haha

 

not sure if that was a good move bro, u should get that thing removed and install a stock AC evaporator. The normal thing would be for the RPM to rise a little maybe up to 1,000 ~ 1,100 depending on weather conditions. Shouldn't shake too much either.

 

I agree it shouldn't shake too much but remember what engine we are talking about. Rotaries are just not best suited for running alot if any accesories. I think alot of people have the problems with the stalling.( i seem to remember a recall or something on the ECU"S maybe?) Like i said I have a stock mazda FD evaporator here. I'll talk to him later today about $ ( He owes me alot for the deals i give him on his car, might be free)When it would shake and stall it was usually when I came off the throttle and straight to idle. It would drop way down almost 0 and come back to around 8-1000 rpm. varied. Even with the A/C removed it screws with the computer and idle by turning on the fan switch( A/C speed) Just too dependent on the electrical systems output.

 

Is the evaporator valve rated at the same pressure as stock? It could be choking everything down and over-working your compressor.

 

Wow this AC system thing is alot more complciated than I thought.. how do i check the valve rat3 thing? would i need to uninstall the evaporator the guy put in.. It really wasn't my choice the AC guy claimed it was for an rx7, the casings looked similar and it bolted right in however he said the one that he was using was american made

 

I need some help here.. I've learned that yes there are two different evaporators one for the US model and one for the japan model. I know now that the evaporator casings are different, so if you end up using the american made evaporator and the american casing will it effect the car if the original casing and evaporator was a japan made one? *the american casing bolts up correctly

 

I would guess the A/C didn't work for you prior to having it repaired, if so its likely the load of the system is not being off set by the support systems. I am new to rotaries but almost all cars have systems which add extra air to compensate the extra load put on the idle. Normally its done one of two ways. The most common would be via the engine computer, it would open the idle air control just a bit and this is normally mapped in the computers Program. The less common and on older cars is ether a throttle up solenoid or a extra air valve which introduces extra air into the throttle-body also this is somewhat predetermined via the factory's expected loads which are associated with the A/C.
If the system works and is not making noises like a faulty compressor etc one of the subsystems are not on line. If it were a General motors car I could point you in the exact direction but rotaries are new to me and I am learning as I go.. I would not run the system until the system is corrected and as for the evaporator being a problem its not likely.

 

Give me another AIM, I ignored you by accident. I got the correct one for you.

 

I would not install another evaporator, thats not your problem.

 

Then what is it? I also saw that you posted about compression checks. Did you do one? results?

 

Hobbe7, I didn't realize you meant an American made evaporator meant for the 7. For some reason, I envisioned the mechanic shoe-horning a generic fit solution.

The evaporator valve's ideal pressure is more or less dictated by the gas/fluid that's being used in the system. Did this repair include a R-12 to R-134a conversion as well?

 

I have no clue..... anyway to check? i dunno this problem is pissing me off esp since the AC guy insist on blaming me when he wouldn't even take a second look at his work

 

There are two different evaporators but I don't know if the one is actually made in America. The literature I've seen refers to the Nippondenso and the MANA (does that perhaps stand for MAzda North America? I have no idea), aka factory installed and port-installed, although again I'm not sure that is an accurate reflection of where and when they're put on the cars. GENERALLY speaking (I'm talking '93 here, I don't know what differences if any apply to the newer cars) the Touring models had the "factory" units, while the others had the MANA. Certainly, it is cheaper to get a MANA replacement than the ND version. This little rule of thumb is not universal however, as I've seen a few exceptions.

jds

 

If anyone has a manual handy I would look at the idle load controls associated with the A/C. Something may be in the wiring diagram pointing to a electrical actuator which in turn preforms a job related to load.