5A-FE idle and acceleration issues

[nosnick07]

Guys i'm having some problems with my recently installed 5A-FE engine in a AE-101 corolla. since the engine was installed the engine idles at a very low rpm which got drops even lower when the ac is on, the idle also seems to be hunting or raising and dropping. sometimes the car would just cut off while i'm in traffic, also i'm experiencing some barely satisfactory acceleration between 0-60km/h. i carried the car to the mechanic who installed the engine and we discovered that the ac step up wasn't working which was part of the orginal 4af engine. So he wired up a 1jz step up unit that he had, but it made very little difference with raising the idle rpm. then we he took out and cleaned the idle speed control valve which made the car function great on the cold start but when the engine gets warm the rpms drop right back down. Then we cleaned the injectors i got a slightly better acceleration but still had a rough and low idle. The last thing we divulged in was checking the timing. we discovered that the timing was wayy off, so he set the timing to the correct setting. but it only made things worse. the idle rpms went up a bit, but it still dropped considerably with the ac load, and the idle still was hunting. also when i drove the car the more i mashed the pedel the more the just bogged down, so the timing was clearly off. We simply had to put the timing back where it orginally was for me to drive the car to work the next day. So as it stands i'm at a total loss at what to do any help would be great.

[Hibrydsoul]

Take a read.... http://www.pakwheels.com/forums/engine- ... on-problem

I'd suggest checking for any error codes, I'm no expert but there are resources available to show you how to check. I'm guessing its an OBD1 engine?. The following thread shows you how

viewtopic.php?p=1883513#p1883513

[Hook]

Sounds like your mechanic rather poke around your engine than make sure everything's set properly from the start. Maybe he likes seeing you...or your money.
I could tell by the way he waited 'til there was a problem before he checked your ignition timing.

Hunting for idle could be caused by many things, including improperly set timing (ignition timing and cam timing), vacuum leaks, or air in your cooling system near the coolant temperature sensor.

I'd make sure everything is set to spec before tinkering with anything.

Check that there are no vacuum leaks anywhere. You'll hear the hiss. If the engine is too noisy to hear it, start the car and spray your vacuum lines one by one with carburetor cleaner. A leaky line will suck up the spray and cause the engine to bog down periodically. Replace leaky lines as required.

If your ignition timing is way off, but the car runs better that way, then your cam timing is off. Make sure all your timing marks line up and THEN you can tinker with the distributor.

First, disconnect your battery so the ECU can be reset while you're working on your timing.

Take out spark plug #1 and insert a wire rod long enough that won't fall in.
take off the cam cover to see the cam gear timing mark and rotate engine clockwise 'til top and bottom parks are where they should be, but observe the movement of the wire rod. It should go all the way up, pause ever so slightly and start to come back down. You'll want it at it's highest point. This is Top Dead Centre, or TDC. Ensure at this point that your distributor's rotor is positioned to fire at plug #1.

Here are your timing marks.


After here is checked and in good order, reconnect battery, open the diagnostic port and use a small piece of electrical wire to jump pins TE1 and E1. When you start the car, this brings everything back to base timing, without correction for air temperature, knock, etc.

Start car, use a timing light and set as desired, usually around 8-10 degrees before TDC.
Switch off car, remove jumper wire from diagnostic port and restart.

Good luck.

[Bigmanbandy]

Sounds like the car not getting enough fuel. Take a small vice grip and clamp it on the fuel return line and make a block. When last you change your fuel filter?

[nosnick07]

firstly thanks guys, for the info. This week self the mechanic checked d cam timing, but he only checked to see if the notches were aligned he didn't check to see if it was at tdc etc. so thanks alot hook for the info and i will put it across to him tomorrow. if when we do it and i still getting problems i will carry the car for a diagnostics test to see what error codes come up. but so far everytime ive checked him he hasn't asked for a cent he was jus more concerned that the engine he installed was giving so much probs. anywho i'll keep u guys posted as to the outcome. thanks again.

[AdamB]

You may want to check that your distributor self isn't defective. I have a padna who just recently had to repair his one, used oned were hard to find and new REAL expensive. Once you confirm it's not a fuel problem, if you have rough idling them it's an electrical spark ignition problem. The timing is important yes, but the current has to be delivered to each plug in the first place.

[Hook]

So he should do ye olde screwdriver test and see if he's getting good spark?

[biller]

Hey I'm having the same problem with my 5a engine in my 101 and no one seams to know what's wrong when its cold it takes a while to get power but once the car is warm it good and with the ac load the idle is low and I loose power what can I do ??

[Mojocars]

Dashpot Adjustment
Cleaning and Adjusting the Miata Dashpot (1.6 liter engines)

Disclaimer:

I am a college student, not a master mechanic. Everything in this article is from the experience I have had on my car, or read here on miata net/other service manuals, and should be taken with a grain of salt. I am not responsible for you crashing your car because of adjusting too much causing WOT.
Pre Dashpot work: I recommend adjusting the slack in your throttle cable (if you have any) before working on the dashpot, as you might have to readjust later. All work should be done while the car is off, and you should have to walk around and turn the car on to re check if the plate catches the rev. (To prevent a noisy neighborhood when you do eventually get stuck at WOT, and the adjustment screw gets freakin shakey)
Before working on the dashpot, a brief explanation of what it does: When you take your foot off the gas, your throttle cable snaps shut. This part keeps the throttle body butterfly valve from closing too quickly, which starves the engine of air. This is what causes your car to stall when you put the clutch in to stop. There are a few different ways to figure out if your dashpot needs adjusting:
Low RPM clutch engaged droops below 850 or stalls
High RPM clutch engaged stalls usually if you do not catch it with a small blip from your throttle.
I cleaned and adjusted the dashpot on the car, as I was about to strip one of the bolts holding it on. I am sure it is a lot easier to clean it off the car, as a soak in penetrating oil or any other caustic liquid (gas) might make everything better.

Tools required
:
8mm combo wrench (2 is better than 1, but 1 will work just the same)
PB Blaster/ WD-40/Engine oil
Brain
Step 1: Locate Dashpot


(if you have gone this far with a 1.8, turn back and re read now, you'll never find it)

2014 06 25 16.00.59[1].jpg


Visual Aid for what I call the parts, by no means the right names
2014 06 25 16.02.34[1].jpg

Step 2: Prep your pot

Take it off the car!
If you cannot do that due to corrosion (that's me),
Hold open throttle with one hand
20140625 155454[1].jpg

remove the black rubber cover from the Dashpot’s cylinder.
20140625 155537[1].jpg


Don’t mind the red lube previous attempt to fix it with wheel bearing grease made it gummier, which might have helped (probably didn't), but people just use PB/WD-40/ or regular motor oil.

Step 3: Blast the cylinder

If you can, remove the dashpot from the car and soak it in a PB blaster bath or gasoline. This will clear out the gunk easier and more effieciently then the following steps.
Face the can upside down (or use the small red tube they send) and blast the dashpot's cylinder and up into the dashpot itself thoroughly to lube and break up the dirt that gunks it up. Make sure the dashpot has about half an inch of play and moves freely without seeming stuck.

Step 4: Adjustment

If you removed the dashpot, obviously now is the time to put it back on. (durr)
The Spec for where the dashpot should be engaging when lubed and working properly is touching the adjustment screw at 2500 rpm.
You might need a buddy for this one, or very good ears and the ability to figure out where your throttle pulley should be at 2500. Take an 8mm combo wrench and loosen the lock nut, then have a buddy sit in the car (or hold your throttle open by hand if you know what 2500 rpm on the throttle pulley like) and hold the revs at 2500 until you are able to line the adjustment screw up to the bottom. At this point all you want it to do it touch, not be dampened yet.
Be sure to re tighten the lock nut. Even though it seemed tight when I first did it, our cars are vibrators on wheels and it lowered after a 5 minute drive down the road to test it, stalling the first time I tried to test.

Step 5: Test it

To check the adjustment, hop in the car and turn it on. Just tap the rev one time. If you adjusted too much, it will stick at the peak of the rev and you’ll just have to go through the steps to lower it again.
I tested mine by starting and stopping. In a series of tests, staying in first or second gear, bring the car to 2k,3k,4k,5k rpm and engage the clutch. Let the revs fall without catching it and you should see it fall slowly down to 850. No more idle dips and stalling for me! I will have to give it a few more days to drive on, but it has held for 50 Miles FULL GAS TANK since I did the change!

[kiran8977]

Most of the time i found with these engines the low idle with the ac on and in a gear and the loss of power comes from the idle control sensor sometimes cleaning can be of no use try changing the idle control with another and see how the car operates