warm start issues on replacement engine
 

Car starts fine when cold.
When warm / hot will start after 10 - 20 turns on starter.
After looking thru threads was looking to take sensors off old engine and replace onto this one.
Have cleaned MAF & changed rear temp sensors and thought all was well - still there.
The engine I'm using was from a 92 salvage and sat idle for 4 yrs I reckon.
Am I on the right track with doing the other sensors or try something else - Car runs fine once it's running - but really feels like it needs to turn over more than it should before it gets running, and I know they normally pretty robust and start straight away

- heading to post count 100!

Re: warm start issues on replacement engine
 

I have had the same problem with mine. I have had many sensors replaced but it still has the same problem. Cold start no problem, warm start is a problem. I have found that one quick punch of the accelerator as it starts to crank seems to give it the ability to start when warm. More than one quick punch will flood the engine so be careful. Mine is a '92 but I don't know the year of the replacement engine. I have put almost 100,000 miles on the replacement engine and it has had the problem since day 1.

Re: warm start issues on replacement engine
 

Sounds like you might have a heat soak issue with the starter (?)
-Bill

Re: warm start issues on replacement engine
 

Many starters, same problem.

Re: warm start issues on replacement engine
 

Hi Mate. There are two main reasons that would cause the starting problem when hot.
First fuel, if if has a leaking injector, or a faulty temp sensor, it can be too rich to start first off, has to be cleared out to go.

The other one is the magnetic sensors like the crank,and cam position sensors. These age with time to lose some of the magnetic strength to produce a weak signal.
It may be strong enough to start when cold, but when they heat up the curie effect causes them to lose more magnetic strength, so that the signal is too weak to produce a constant signal, takes more turning for the ECU to trigger the injectors and spark.
Try swapping the ones out of the old engine, both cam and crank.

Harvey.

update
 

progress has been made - will post here so it may help others (frustrating doing the searches and most are dead ends)

Installed the 2 cam & 1 crank sensors + 2 knock sensors.
Removed the alternator - then did it the hard way by leaving the plenum on to do the knock sensors.

All good - problem fixed. Looking at the removed sensors I'd guess the knock sensors were playing up when hot, other sensors were just dirty.

At least it was not the wire harness for the engine which I was dreading - it is quite hard and brittle.

Now starts first go every go - just like the maker intended.

Thanks for the inputs

bruce:)

Re: update
 

The magnets in the position sensors Will have the magnetic field shorted out by iron/steel filings across the face, can be cleaned and reused.
Looks like your problem, good work.

Harvey.

Re: warm start issues on replacement engine
 

Hey I just changed the cam, cam and crank sensors, the car starts and drives so different now

Before:
Cold start - fine
Starting after immediately switching off - fine
Come back 2 or more hours later to start - engine turned over and over and over

My idle was low before, and now it's back up, my idle was at about 400rpm, at or below (in drive) the first line from 0 on the tachometer, the car vibrated because the idle was low, you could feel the fans kicking in and out and any rpm fluctuation SO ANNOYING!!

Now it's good as gold, idles at the 1st line below 1000rpm

I can take a picture of my old sensor if you like

Jordan.

Re: warm start issues on replacement engine
 

appears problem is still there.

Cold Start - instant ignition
warm start - short stop - instant ignition
warm start - 20min stop or longer - very hard to start - 20 / 30 cranks
let car go cold - back to instant ignition.

so the fact if it cools down then starts indicates there is obviously fuel

could it be coils & H/T leads, weak earth somewhere when hot?

has to be something specific to this engine as previous engine was a well behaved one!

Re: warm start issues on replacement engine
 

That could be a leaking injector, slowly fills the manifold with fuel when it is left long enough.

Harvey.

Re: warm start issues on replacement engine
 

maybe temp sensor ? i've had a subaru throw crank and cam sensor codes from cranking too long when it really was the fuel pump relay not working. So whats different on this motor to the old one? which sensors are from the old engine which are not? change all of them over does it still do it ?


cam

Re: warm start issues on replacement engine
 

You never know, the crank sensors are very old.. from both engines.

When you drive the car for about 30mins+ come to stop with the car in drive, see what your idle revs are at... in drive.

If the pointer is just at the first line above zero (don't quote me) but that indicates something isn't right.

Has there been noticable changes since changing the vacuum lines?

Re: warm start issues on replacement engine
 

will try changing the fuel rail and injectors, then H/T leads.

Getting no codes at all - car really runs great except for this warm start problems - even get the feeling the engine has stalled when at lights and you can't even tell it's running.

BTW - when they list our injectors as dual injection - do they refer that it does entry thru each inlet Vv, 2 per cyl or it does a double pump or something.?

Re: warm start issues on replacement engine
 

The SVX does not have H.T. leads as the plug mounted coils are supplied at low voltage. However the insulation associated with the coils and plugs has been reported as breaking down after becoming hot, but if so one would expect constant erratic running after becoming hot.

When the trouble is apparent, put your thinking cap on. You have been given several tips on what to concentrate. ;) Don't put yourself down as not having the required experience. Common sense is top of the order. :)

Sorry I have not seen the injectors described as dual injection.:confused:

Re: warm start issues on replacement engine
 

Hey Bruce, hope you get this.

My SVX is also having warm start issues which I can't seem to find.

After reseting the ECU, the problem seems gone but a couple of days later it comes back.

It should be either gound wires, ignition switch or starter motor.

I have had an ignition switch code a couple of months ago, reset it and it never came back.

Very annoying problem!!
especially after spending close to a $1000 in engine sensors.

Jordan,