Hot starts on the V8

[lotusespritse]

How long does it take for your V8 to start up when it's hot?

Slow hot starts seem to be a common concern, but I have heard some say it's a design feature and not a problem.

My car fires right up when cold. But takes a count of 5 to start when it's hot.

[LotusGuy48]

My 2001 Esprit V8 is exactly the same. Starts right up when cold but when hot I need to keep the engine cranking continuously for about 3-5 seconds before it fires up.

[Sburke]

I saw a V8 over the weekend. We both pulled up to Starbucks at the same time and when he was leaving it took awhile for it to start. It seems like there are a fair amount of videos like that on youtube as well.

[ESPREE]

Once I added the additional ground wire and replaced the cam and crank sensor, my hot start problem went away. It also starts the same hot or cold. I'd say 2-4 seconds.

[lotusespritse]

Originally Posted by ESPREE

Once I added the additional ground wire and replaced the cam and crank sensor, my hot start problem went away. It also starts the same hot or cold. I'd say 2-4 seconds.

Very strange that it can take 4 seconds for your car to start when cold. Mine jumps to life when it's cold. Most people seem to have a super fast cold start -- but I guess I should have a poll for that as well.

I am trying to gauge if I should spend any time on improving the hot start time, or just leave it alone.

What is consistent is that if anyone hears my car take 4-5 seconds to start hot, they think something is wrong with the car and start to get that sympathetic your-super-car-just-broke look on their face.

Fuel injected cars have gotten everyone used to a fast start. If a regular FI car doesn't fire in the first 2-3 seconds, it's not going to start period. Gone are those carb days where it was common to have starting problems and learning how to deal with them without flooding the car. I hated those days.

[Zippy_Slug]

Mine doesnt seem to care whether it's hot or cold.. sometimes it takes a few seconds to start, sometimes it turns right on.. regardless of hot or cold..

[ESPREE]

Originally Posted by lotusespritse

Very strange that it can take 4 seconds for your car to start when cold.

Let me take that back. Here's a video of mine starting cold, and it's probably 1-1.5 seconds:
1999 Lotus Esprit V8 engine rattle - spun rod bearing noise - YouTube

With the hot-start fixes mentioned above, it is now the same when hot.

I know what you mean about the long starts - when I was having the hot-start issue it would take me like half an hour of on and off cranking to get it started (basically it would only start once the engine cooled down).

So it was a huge relief to get that fixed!

[lotusespritse]

Originally Posted by ESPREE

Once I added the additional ground wire and replaced the cam and crank sensor, my hot start problem went away. It also starts the same hot or cold. I'd say 2-4 seconds.

Did you ever use any ODBII software/tools to confirm the sensors weren't working, or did you just change them?

I am going to have to look to see if the free V8 software knows how to report on them.

Update: Doesn't look like it does. I wonder if the Tech-1 can do it?

[jtrealty]

I had a very bad hot restart problem. It was so bad it cranked slowly as if the battery was weak. Jumping it helped but it still had to crank an excessively long time. Did a lot of things to try to fix it. The problem eventually turned out to be bad primary injectors. A Tech 1 won't find this. If you have anywhere near 40,000 miles the original injectors are shot. FiveoMotorsports.com. 1995 Cadillac 4.6L injectors. Cost me $342 + shipping. Now it starts up even better cold AND hot! Bet that is your problem too. The bad news is you have to pull the intake plenum to get to them.
David Teitelbaum

[lotusespritse]

Originally Posted by jtrealty

I had a very bad hot restart problem. It was so bad it cranked slowly as if the battery was weak...The problem eventually turned out to be bad primary injectors.

David, that really seems unlikely that the fuel injectors going bad could cause the starter to not have enough power to turn the engine over with authority.

If you look at Section ML sheet 4, you can see that the starter motor is directly connected to the battery positive terminal through an unfused connection to a big relay with large gauge wires.

All 10 of the fuel injectors and the primary fuel pump go through a 25amp fuse, section ML sheet 5.

25amps is chump change compared to what a starter pulls. Most small batteries can do 800 cranking amps.

I don't doubt that fuel injectors go bad and need replacing, but I really doubt that bad injectors could cause the starter motor issues you saw unless the cylinders were being filled with so much gasoline that the starter couldn't turn the motor because of the increased compression. But I am sure you would have seen some other explosive symptoms if that was the case, and the car wouldn't run at all, not just be hard to start.

I am thinking by doing the work that including removing the plenium, you must have somehow improved the connection to the starter or the ground wires since the starter is accessed through the plenium too. So you would have fixed 2 problems instead of 1.

[ESPREE]

Originally Posted by lotusespritse

Did you ever use any ODBII software/tools to confirm the sensors weren't working, or did you just change them?

I am going to have to look to see if the free V8 software knows how to report on them.

Update: Doesn't look like it does. I wonder if the Tech-1 can do it?

We did indeed check for ODBII codes or issues - nothing reported (which made diagnosis difficult).

[mac2000]

I also have a hot start lag. Where did you anchor the second ground wire to the frame? I may try that first before trying cam and crank sensors.

[ESPREE]

Originally Posted by mac2000

I also have a hot start lag. Where did you anchor the second ground wire to the frame? I may try that first before trying cam and crank sensors.

We ran a large gauge wire from the block right to the battery. I have one of the Optima batteries that has both top and side posts. The top posts are the "normal" connections, and so the new ground connection went right to its own terminal on the side. Easy enough.

You could also just setup a quick test with something like jumper cables I suppose.

If that doesn't work, then go for the cam and crank sensors. Basically they work fine when "cold", but the electronics fail to initialize properly when they are hot.

[jtrealty]

There have been cases where the "O" rings on the secondary injectors leaked and caused hard hot restart. When I convinced myself this wasn't my problem I started looking elsewhere and that's when I discovered the primary injectors were leaking. It all started to make sense when reviewing the service history and the fact that a PO installed a MUCH taller and bigger battery. This problem must have been plaguing the car for a while. I would agree with you it doesn't make sense but I did not change the battery or the starter or the wiring, just new injectors and that fixed the problem. Yes, I did R & R the intake plenum numerous times but till I changed the injectors nothing improved. Once I started talking to Five0Motorsports and learned more about the injectors it all made sense. The OEM are pintle type and by 50,000 miles they are no good. The newer, disc type are supposed to last much longer (that is what I now have). The insidious part of this is that you do not throw codes with leaky injectors so a scanner will not help you. You need a fuel pressure gauge. Not only do you have too much fuel before you crank the motor, while you are cranking, too much fuel is leaking out of the injectors and vaporizing.
David Teitelbaum

[gmendoza]

Mine starts within 2 secs regardless if its hot or cold. Sometimes it will take 3 secs but that is very rare. Here are two examples of how my starts usually are:

Two Lotus Esprit V8s Start Up & Drive By Video - YouTube

Two Lotus Esprit V8s Start Up & Drive By Video - YouTube

[mac2000]

The injector body for the 2000-2004 lotus v8 at FiveO seem to be made of grey plastic. Is this the type you used?

[jtrealty]

I don't remember the color. Talk to them over at FiveO and they will set you up with what you need.
David Teitelbaum

Originally Posted by mac2000

The injector body for the 2000-2004 lotus v8 at FiveO seem to be made of grey plastic. Is this the type you used?

[irox]

Originally Posted by lotusespritse

Very strange that it can take 4 seconds for your car to start when cold. Mine jumps to life when it's cold. Most people seem to have a super fast cold start -- but I guess I should have a poll for that as well.

Mine is instant start when cold. And dependably slower when hot. Maybe 2 secs.

[BlackSheep]

Mine starts instantly, hot or cold.. Is there a check valve in the system that when warm could be the culprit?

[lotusespritse]

Originally Posted by BlackSheep

Mine starts instantly, hot or cold.. Is there a check valve in the system that when warm could be the culprit?

That's the rub. Lot's of threads about the issue on other forums, but no one can pinpoint the cause for all slow hot start problems.


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