New engine: how soon to Auto-X?

[turtle8]

Hey folks,

I am sure this has been discussed before. I've got 100 miles on my new engine. When can I thrash it?

[MiataMania]

Now.

[tedebayer]

You'll probably get a lot of opinions on this, here's one

First - define new engine. New to you? Just rebuilt? You do the rebuild?

Second - IF just rebuilt, I'd put 150 miles on it , change oil and filter (I'd strain it but I'm a freak) and check over nuts and bolts just to be sure nothing is loose. Stand beside engine and rev it... listen for BSRs. (Bumps, Squeaks and Rattles). 150 miles is about right for exhaust manifold bolts to need re-tightening. If you don;t, it MAY blow around your gasket and get noisy and idle terribly. Cold start and check exhaust and see if any white smoke or other extraneous liquid stuff at tail pipe.

Third - If it's new to you, check it over as above and run it now but keep an ear on it. It's easy to say, "you have nothing to lose". And that is true, up until some thing blows a "peeker" hole in the side of your block giving you a un-rebuildable engine in a lovely paperweight in the shape of a Miata for your garage floor.

That's an opinion. I'm sure you will hear others. Listen to all and make your best judgment. Ultimately, you will pay most so you should get to decide. ;D Best of luck.

[turtle8]

I just rebuilt it. New everything except rods.

• Bored .040 over
  
• New stock type pistons and rings
  
• Reman. crank
  
• Matching bearings
  
• Rebuilt cylinder head
  
• New water pump
  
• Timing belt kit
  

It runs fine except I have one minor issue. At cold start it starts and idles just a little rough for a minute or so. When I mean it starts rough, there is a slight shake to everything. Once warmed up it idles fine. I've got no check engine light. Going down the road it is great.

[wcox32408]

Have you had the car scanned? sounds like a sensor issue. how is the compression across the cyls. while cold? warm? I will have my Modus scanner from the shop with me on the 20th, or if ya want to meet before then let me, I drive from mooresville to winston salem everyday.

[turtle8]

There is no check engine light that would indicate a code. There was a code before that showed an EVAP code P1494 (Leak Detect Pump Switch or mechanical fault). I reattached a breather hose and cleared the computer. Since then, the code hasn't come back.

I haven't checked compression since the rebuild. Before the rebuild compression was bad and vibration was horrible. Like I said before, now after a warm up, it runs great.

[wcox32408]

could be tps or iac.

[slobra]

Drive it like you stole it...just kidding
When I bought my Bullitt, I drove it to Greensboro with less than 200 miles by the time I got there to a T-N-T. 2 Weeks later to GA for the national tour, it had less than 1000 mile when we got there. But I agree with Ted. About another 50-75 miles, then check all the nuts and bolts. Anything that is easy to put a torque wrench, make sure it is torqued to the right spec. Most of all, Ted's advice is for general things. there may be some Neon issues that only Neon people would know about. I don't know much about Neons other than my mother drives one. LOL

[cr89x]

Idle issue: triple check coolant level. Probably nothing to worry about much check motor mounts as i'll state below.

I agree with Ted for the most part. You do need to double check alot of bolts and torque specs. My only concern is the 150 miles ... to check over the bolts that is fine, but to go thrash it I would be leary.
I've lived by the 500 mile rule. Doing breakin, changing oil, checking bolts. Also a good note is how you break the engine in. Don't maintain an rpm for too long. You want to vary rpm. Also try not to go over 3.5k for first about 200 miles is what I do. Slowly get it aquanted with abuse you know. I could go more in depth, but I'm sure you know not to go out doing burnouts and trying to race John Force so soon.

There are a couple weeks until ZMAX, keep driving it and you'll be fine. By then mileage isn't so important, you've ran the engine enough and it's time to reap the benefits of all your hard work. Just hope your not driving it a short ten minutes at a time.

[loves2turn]

I know a hand full of people who break in their engines on the dyno.

I doubt its an IAC problem..the car would idle terribly ALL the time. The TPS sensor would cause hanging idle..so you can rule that out. Check your motor mounts..my car runs sluggy for about 10 seconds in the morning and vibrates everything in the car. Worn mounts can make it feel terrible.

I have seen cars run bad with a faulty CTS (i have a spare working one), also..check your cam and crank sensor. Evap wouldnt change how the car runs..just emissions.

With my camaro..we broke the engine in on the dyno, beat the crap out of it for about 100 miles..changed the oil and filter and the car is running like a champ. Even DCR and Mark Riley of Turbo Tune suggest breaking a race engine on the dyno.

[turtle8]

I've only been driving it around town.

A short trip is about 15min.

The RPMs vary in city traffic. Did the ring seating process as outlined in the Haynes manual. 30mph to 50mph, lift the accelerator to coast back down to 30mph - ten times.

New mounts might fix the squeak. Thought about control arm bushings.

Cam position sensor is new. I was getting a code there, but after the new sensor, it has gone away.

Hopefully by zMax, the mileage on the odometer will be up there.

[turtle8]

!@#$%^

EVAP code came back today.

Cold idle is rough, like it is misfiring.

After a short warmup, the idle smoothed out about 95% good.

No other engine codes.

Could not find any vacuum leaks. Hoses appear to be routed correctly.

[loves2turn]

Search for vacume leaks, particularly around the intake manifold area (IM to Head, Upper runners to plenum, TB gasket), vacume lines going from TB to evap equipment, fitting comming out of the IM that the evap hoses connect to

[turtle8]

Previous owner had no gasket at the throttle body. Used RTV. I did the same - oops. Doesn't appear to leak there.\

Intake manifold bolts near the center in the top row were a tad loose.

Clamp at the intake end of the manifold to PCV hose was a tad loose. Oil can be seen on the outside of the manifold at that spot.

Tested the MAP sensor for the IAT (intake air temperature) voltage. Specifications are 4-5 volts with the ignition on while the engine is NOT running. Tested voltage is 2.3V. With the engine running at idle, the voltage should be between 1.5V - 2.1V. Tested voltage is 2.3V while the engine is idling. That would indicate to me that the sensor is faulty. A new sensor is $85.99 at the local auto parts stores.

[cr89x]

Did you do the test at operating temperature though? That will throw off the reading. You may need to look at a new pcv valve if you continue to see excessive amounts of oil going into your throttle body. Quatripdup... check your mechanical timing. Be sure that you didn't at all either.

That Haynes manual break in doesn't sound too terribly bad. My concern is the short trips. You should go take some long trips up the Interstate to help it all out.
I agree chad about dyno break ins. They make life so much easier. I've broken in most of my engines with highway trips. Boring but it's well worth it. Just have to watch hanging rpms for too long.

Really hope everything gets sorted out by ZMAX for you.

[tedebayer]

AJ...funny you say that. It reminded me...

I have owned over 80 cars in my life. I have made a lot of mistakes and broken a lot of parts. I have found that things break two ways statistically:

1. Long extended use - long trips, high heat, high revs...highway miles.

2. Sudden on and off. Jumping on the gas or brakes or yanking the wheel.

With hillclimb, I have found the ultimate way to destroy parts and make things break. I am covered on high heat, high revs, jumping on the gas, jumping on the brakes and yanking the steering wheel. I just have to stay off the highway for extended periods of time.
;D ;D


Teapot Photo by Richard Hunter

Towing Service by The Happy Hooker

[turtle8]

I drove around for about 45 min yesterday. On the highway, my Neon is smooth as silk. At the normal shift point of about 3500 rpm, the cabin vibrates and resonates. It is annoying; probably because of my filled, front motor mount.

Feb 8, 2010 9:19:29 GMT -5 cr89x said:

Did you do the test at operating temperature though? That will throw off the reading. You may need to look at a new pcv valve if you continue to see excessive amounts of oil going into your throttle body. Quatripdup... check your mechanical timing. Be sure that you didn't at all either.

The telltale sign is that the voltage didn't change from when the ignition switch was on while the engine is not running to when the engine was at idle. When the key is on (engine not running), I am supposed to have the same output voltage as the input voltage, but I don't.

BTW: Last night when I drove home from my sister's after the Super Bowl, it was cold outside and the engine ran like crap.

[cr89x]

Funny Ted. I do agree. Of course we all know that there are always different ways of doing things and everyone does so differently as well.

hmmm... mike. You may need to check that coolant level again. Maybe an IAT issue. Sounds very familiar to my CRX right now. It won't run worth a darn until it comes up above 150 degrees Farenheit. Doesn't bother me though. I think i've narrowed my issue down to fuel pressure and spark plug issues. Fuel pressure being too high for the crappy Bosch plugs I have in it right now.

[loves2turn]

Mike..the IAT is integrated with the MAP in one sensor..i have a spare working sensor i can bring by later this week..althought ive never heard of one crapping out..id rule out the CTS before that.

[turtle8]

I'll test the CTS.

I double checked the IAT at operating temperature. Iginition ON voltage climbed to 3V (should be 4-5V). Idle voltage climbed to 2.79V (should be 1.5V to 2.1V).

BTW: The EVAP code 31 (P1494) disappeared. I am sure it will come back.

[cr89x]

That would be a Leak Detection Pump switching error. Check your wiring to the pump behind the passenger headlight.

[turtle8]

Feb 8, 2010 18:53:58 GMT -5 cr89x said:

That would be a Leak Detection Pump switching error. Check your wiring to the pump behind the passenger headlight.

Yeah, I checked all that and it looked fine. Tomorrow I'll go over it again.

[cr89x]

If you need a diagnostic chart let me know.

[turtle8]

Feb 8, 2010 20:21:28 GMT -5 cr89x said:

If you need a diagnostic chart let me know.

I've got an alldatadiy.com subscription. I don't have what they call a DRB to test the EVAP system.

[cr89x]

I didn't read it word for word, but say voltage checks and use of a vacuum pump. You should be able to figure it out. The only real problem that EVAP code will cause you is inspection time. Seems like it is just a LDP switching issue.

[turtle8]

Will that EVAP fault cause fueling or injection issues?

[cr89x]

I can't give you a definative answer on that one. It seems like it is more of "Is the LDP working?" than there is a leak.

[cr89x]

Is DRB a manufacture specific scan tool? My flow charts do not mention it. They mention a standard scan tool. Something I'm fairly sure my Snap On can do. Basically making sure the switch is switching and making it switch.

[turtle8]

This is all the info I have:
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[loves2turn]

The EVAP is there merely for emissions purpose's. It wont affect fuel or fuel injection. It just wont "vent" the gas fumes properly. When using an AFX-R ECU, you can actually remove EVAP without it tripping a CEL and pass emissions.

I have a MAP/IAT, and a CTS..ill bring both..we can swap on both and see what happens. Other than that you still have your Cam sensor, and Crank sensor on the back passenger side of the block. I dont have spare sensors but the JY does.