WARM START FIX

tdi-man

Registered User
Joined
Jul 27, 2009
Messages
1,713
Reaction score
65
Points
48
Location
NULL
why is it some cars need a warm start map to make car start first turn of the key when warm.

i have this in mine but wonder since ive had a new head and bottom end rebuilt if i need it .

going for another map soon
 
I have this problem takes 3/4 turns when engine is hot. Anyone know the cheapest and quickest way to resolve it?
 
Coolant temperature sensor gives this fault.
 
I had it mapped out. Wouldn't tell me what the actual cause is but it's been spot on since.
 
I had it mapped out. Wouldn't tell me what the actual cause is but it's been spot on since.

How much was it and where can you get it done from. If I get a remap done will that solve the issue?
 
New battery fixed it in my case.
 
I changed every Think didn't fix it so was mapped out.
 
I checked/changed loads of things, nothing worked so I got it mapped out when I got my car remapped from R-tech.
 
emznjav:1958778 said:
I had it mapped out. Wouldn't tell me what the actual cause is but it's been spot on since.

How much was it and where can you get it done from. If I get a remap done will that solve the issue?

Was done by a Quantum tuning rep locally. Got it generically mapped at the same time and had the EGR light disabled. Think it cost about 180 for the lot. I had to request the hot start fix and EGR.
 
Coolant temperature sensor gives this fault.

Ive tried this when I have removed the coolant temps sensor off and it still does it? is it the crank shaft sensor? or the clutch?
 
Was done by a Quantum tuning rep locally. Got it generically mapped at the same time and had the EGR light disabled. Think it cost about 180 for the lot. I had to request the hot start fix and EGR.

Had quantum map on mine, hows it been on ur car? i never thought to ask them about the hot start fix :/
 
Last edited:
Apart from the turbo recently blowing lol? I'm pretty that is a turbo issue and the map didn't cause it though. The extra strain might not have helped but it was going to go eventually.

Happy with the map. Power wise it was conservative but MPG increased by about 10% on a good run. The hot start fix worked and has been fine ever since. I doubt they would charge much just to add the hot start to your file.
 
I need help! Hot start problem!

I have a 1.9tdi PD105 which used to take ages turning over when warm. On cold start its fine, however it used to turn over for ages till it actually fired up. I had it remapped to 135bhp by Midland Remaps and he cured the problem. He said it is a common fault being a slow crank speed, so he set the ECU to send the fuel in sooner causing it to fire up first time every time.

HOWEVER! Around 10,000 miles since the map, on hot start there's been a couple times where it just about turns over and just gives up and simply doesn't start, literally like as if the battery is dead, the battery test shown that its still strong. So I have no idea what it is? Starter motor maybe?

Its like the car picks and chooses when it wants to fire up on hot start. Sometimes it turns over really slow but still fires up, sometimes there's no issues, and twice now it just hasn't started until the engine cooled down.

Thanks, Gavin
View attachment 27740
 
Your tuner is correct. The hot start problem is caused by a lazy starter motor. The ECU doesn't inject fuel on a warm engine until its over about 280rpm. On a cold engine it injects fuel straight away to help it start.

It sounds like your mapper has lowered that 280rpm figure, which helps it start when hot. The problem is now your starter is so lazy that it struggles to get to the revised figure.

People often think a coolant temp sensor is at fault, because when you unplug it the car fires first time. This is because the ECU defaults to a cold start when it has no reading from the sensor.
 
  • Like
Reactions: Lenos, kanecullen89 and SAiLO
Your tuner is correct. The hot start problem is caused by a lazy starter motor. The ECU doesn't inject fuel on a warm engine until its over about 280rpm. On a cold engine it injects fuel straight away to help it start.

It sounds like your mapper has lowered that 280rpm figure, which helps it start when hot. The problem is now your starter is so lazy that it struggles to get to the revised figure.

People often think a coolant temp sensor is at fault, because when you unplug it the car fires first time. This is because the ECU defaults to a cold start when it has no reading from the sensor.

Excellent advice. Makes a load of sense. I'll be getting the starter motor changed today and I'll let you know how i get on. Many thanks.
 
It`s nothing to do with the map , my brother was checking for error codes on mine and on doing this he noticed the **** slow warm start issue . He promptly did some googling as he remembered something about it , then he advanced something witch actually worked . So i don`t know how but it can be done on VCDS and ever since has started really well when warm
 
So he may have advanced the fuel injection point on a hot start?

Which is exactly what we have being saying. Maybe we were a bit lazy and called a software change a "map". However, the principle remains the same.
 
So he may have advanced the fuel injection point on a hot start?

Which is exactly what we have being saying. Maybe we were a bit lazy and called a software change a "map". However, the principle remains the same.

hot start fix is definately done in the map ,never heard of any fix via vcds . fuel isnt injected if the rpm is too low .
 
That's what I thought. It was the previous poster who suggested it was done via VCDS.

I've only ever seen it done through a map. Although it can be done without a performance gain, so not necessarily part of what most think of as a "remap".
 
Well my car starts better than it ever has and it has not been near a mapper . I will ask my brother what he did later in the week
 
Let us know alastair, would be interesting to see what he changed to see an improvement.
 
No, i ******** around for hours trying to get the cam timing just right . It was no better so i gave up , he fixed it in no more than 5 min , i`ll see him thursday so i will ask
 
hot start fix is definately done in the map
 
I have this problem takes 3/4 turns when engine is hot. Anyone know the cheapest and quickest way to resolve it?

In Relation to having warm start issue fixed by probably remapping engine into map relating to automatic so starts easier personally i would keep car mapping as it is,some warm starts are almost impossible to diagnose without throwing money at it

Trying to solve this problem myself reading many forums .Some fixed theses but i'm none the wiser-
109 relay but seems car won't start if this was faulty and could cut out as if engine switched off
new battery
starter motor
(engine takes more to start when warm so not spinning at correct speed 2700rpm if i remember correctly were as cold start uses glow plugs and less spin )
coolant sensor even running at 80c still sends signal cold (don't replace with ebay cheap crap original is about £40 and get retaining clip and new seal as these will be break or seal worn)
Mass Flywheel sound crazy but some people problem was when they did get it started was like engine was coming out the car ,on forum member couldn't stress enough it was mass flywheel and solved some peoples but not going there until i'm out of options .
some say depressing the clutch and starts easier (might be ones with Mass flywheel prob) and others say when slowly pressing gas pedal starts a bit easier which i have ,will let you know if i get to the bottom of the problem as VCDS show no fault
Camshaft Sensor was another

IF ANYONE CAN CORRECT OR SHED LIGHT ON THIS RESEARCH MUCH APPRECIATED
 
Last edited:
Some info that also might help someone

Now onto VAG COM/VCDS

Coolant temp check.

This can also be done using something like a ScanGauge or other OBD2 gauges.
On Vag Com main screen click "Select Control Module" then "01 Engine". Wait for it to connect to the ECU then press "Meas. Blocks 08". Below group select 001 and press "Go!" this should show engine speed, coolant temp etc.... Take for a drive to get the car up to temperature, you don't have to log it you can just glance across to see the temperature to see what it reaches. You should be seeing a temp of between 87-92 on normal running temperature. To start with mine was showing 79-80, so constantly running in cold start fuelling - increased fuel to help raise coolant temps. If you are seeing low coolant temp figures this is probably a good time to replace the coolant temp sensor and the thermostat in one go.

IQ and Cam Timing

With the engine warmed up pull over and let the car idle for a minute with all lights, air con wipers etc... off, no extra load should be on the engine. In measuring blocks enter group 015 and press "Go!". Check the second block across, "Inj Qty. (Actual)" This ideally should be between 3-5. Higher number means leaner, lower number means richer. In my case this figure was around 1.4-1.8 at idle, very rich.

Also at idle enter group 004 and press "Go!", look at the last block, torsion Value or i think it might be Synchro angle. In spec should be between -3/+3, the closer to 0.0 the better ideally, maybe with a slight advance in timing, 0.5-1.0.

Write both of these down.

From what i can see in my tests IQ and also the shudder is tied to the timing shown the last block of group 004. If you have anything other than the spec range of -3/+3 then chance are your cam timing is out which is causing rough idle due to the incorrect timing and extra/less fuel being injected.

The A4 is very easy to change the timing slightly on as you only have to remove the engine cover and the cambelt cover to get access so it makes doing this procedure very quick.

For most of the above this is a great guide to follow.
How to adjust rough idle and camshaft timing on VW and Audi TDI pumpe duse engine

My car was showing a Synchro angle was between 7.7 and 8.3 advanced. After i loosened the 3 x 13mm nuts I put an 18mm socket onto the centre of the sprocket and actually turned clockwise to get it to 0. The guide doesnt seem to agree with this. Its a trial and error procedure, undo the 3 nuts, move slightly, and i mean slightly, tighten up, jump back in the car and check the synchro angle in block 004 once again. Repeat until you get to 0.

On my first go i rotated my wrench on the 18mm socket anti clockwise too much following the guide and the car would not start. Went back the other way towards where it was and it started no problems and the angle went down to 6.6 so kept moving clockwise until I reached 0.0. I very much doubt this small change of timing will cause any mechanic problems as its quite a low compression car which will easily run with the timing out a tooth (it wont run great tho but wont smash valves into pistons in my opinion). The movement needed to get down to 0 is very slight so make small movement first to get the angle value down. This is very import and saves a lot of timing going back and for the engine and vag com.

Now check to see if the IQ has been raised or changed as a result of this timing, again 3-5mg/st is what your aiming for.

My car now idles perfect, power is now night and day different to what it was and hopefully MPG will improve as a result. I personally think the timing belt is actually out an entire tooth and the adjustment made doing this procedure just compensated for it.

Things to also check.

Log MAF and boost values for issues. Ideally blocks 003, 011 & 001. MAF values on a 130 should be 850+, you can check against requested. If too low replace MAF. Is duty cycle on 011 is high chance are you have a boost leak or a turbo/n75 problem as the car cannot reach its requested boost.

Here are some logs i took, 3rd gear, 1500 rpm to high up the rev range.
PD130 Logs - Help - SEAT Cupra.net - SEAT Forum

Boost leak test. I pressurised my intercooler system to look for leaks.

I also replaced all my vacuum hoses as they were fraying and split in places.

The solenoid to the EGR valve and ASV, part of the N75 vacuum lines can fail. Try blocking off the connection off the top of the EGR valve to see if this helps. You can bypass the entire ASV and EGR system if you want. My car now runs a single 3mm hose with check valve as per OEM setup to the N75 from the vac source at the back of the engine and a vac hose to the actuator. Everything else is left alone and connected electronically. This is a basic EGR delete.

Hope this helps. and found with research on net and thanks to person who wrote it
 
Last edited:
I need help! Hot start problem!

I have a 1.9tdi PD105 which used to take ages turning over when warm. On cold start its fine, however it used to turn over for ages till it actually fired up. I had it remapped to 135bhp by Midland Remaps and he cured the problem. He said it is a common fault being a slow crank speed, so he set the ECU to send the fuel in sooner causing it to fire up first time every time.

HOWEVER! Around 10,000 miles since the map, on hot start there's been a couple times where it just about turns over and just gives up and simply doesn't start, literally like as if the battery is dead, the battery test shown that its still strong. So I have no idea what it is? Starter motor maybe?

Its like the car picks and chooses when it wants to fire up on hot start. Sometimes it turns over really slow but still fires up, sometimes there's no issues, and twice now it just hasn't started until the engine cooled down.

Thanks, Gavin
View attachment 27740

Gavin was it the starter ,when you said slow turning over then i would have said starter as takes lot less power when cold reply apreciated