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Ive had my 4200 since 2018.
It presented at the PPI with a hot start issue. The ECU stored the same coolant temp sensor related fault. I bought the car. We changed the temp senor. It didnt cure the issue.
Since, I have changed the plugs, sonic cleansed the injectors, replaced the carbon canister, the purge ( aka washing) valve, temp sensor,( again,) thermostat, fan resistor, and crank position sensor....Further, I have cleansed the intake side and throttle body, replaced the air filter and breather hose that was cracked, and cleansed the MAF as we suspected an over filling of oil had seen it covered in oil vapours apreviously
The issue persists...
There is no smell of fuel..it always actually starts, albeit in the laziest, teetering on a knife edge, hardly bothering at @500rpms kind of way....
I have started to show it what my right foot is for these days....

After all the hours spent under the hood of this car, ( I have done a lot of the wrenching on this motor myself) , not to mention the bills Ive paid at a respected indy servicing workshop here in the UK, Im inclined to satisfy myself with the notion that its simply an awkward SOB...
Someone suggested I spend another chunk on replacing the binnacle interface. Im not convinced. But Im ignorant. And ground down, admittedly...
In the final analysis, it does actually start. And it serves to hide the atrocious rattle from oil drained variators...Something else the Indy has suggested is "nothing to worry about"...
Does it annoy the sh1t out of me..? You bet. Having spent money and time, a lot of time, on the car...it bugs the bejeesus out of me..
Can I live with it..? Huh. Im trying not be anal...and it s abig hole ive dug for myself by now !!
I bet you never find anything wrong with it o.p.
Just my twocents....
 

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Discussion Starter · #23 · (Edited)
Ive had my 4200 since 2018.
It presented at the PPI with a hot start issue. The ECU stored the same coolant temp sensor related fault. I bought the car. We changed the temp senor. It didnt cure the issue.
Since, I have changed the plugs, sonic cleansed the injectors, replaced the carbon canister, the purge ( aka washing) valve, temp sensor,( again,) thermostat, fan resistor, and crank position sensor....Further, I have cleansed the intake side and throttle body, replaced the air filter and breather hose that was cracked, and cleansed the MAF as we suspected an over filling of oil had seen it covered in oil vapours apreviously
The issue persists...
There is no smell of fuel..it always actually starts, albeit in the laziest, teetering on a knife edge, hardly bothering at @500rpms kind of way....
I have started to show it what my right foot is for these days....

After all the hours spent under the hood of this car, ( I have done a lot of the wrenching on this motor myself) , not to mention the bills Ive paid at a respected indy servicing workshop here in the UK, Im inclined to satisfy myself with the notion that its simply an awkward SOB...
Someone suggested I spend another chunk on replacing the binnacle interface. Im not convinced. But Im ignorant. And ground down, admittedly...
In the final analysis, it does actually start. And it serves to hide the atrocious rattle from oil drained variators...Something else the Indy has suggested is "nothing to worry about"...
Does it annoy the sh1t out of me..? You bet. Having spent money and time, a lot of time, on the car...it bugs the bejeesus out of me..
Can I live with it..? Huh. Im trying not be anal...and it s abig hole ive dug for myself by now !!
I bet you never find anything wrong with it o.p.
Just my twocents....
Thank you TimR,
Thanks for your thoughts, but that would mean that our cars would fall into the category of "They all do that, Sir", which I hope is not the case - so I'm still living in hope of curing it.

I have plugged off the Purge Valve which has a very slight leak and I've then done my best to simulate the situations where the engine has failed to start from hot shortly after shutting it down, so far without "success", which is of course good news. However it's by no means conclusive since my failure to start from hot didn't / doesn't happen very often.
On Thursday just gone I ordered the following parts that are relatively easy to replace (compared to changing the Crank Sensor):- 180861 (Washing/Purge Valve), 220074 (Fuel Vapour Filter), 230890 (Thermostat) and 137873 (Gasket for the Thermostat). They are due to arrive on Tuesday. I shall then start by comparing the vacuum retention of the new Purge Valve with that of my old one, and then fitting the new one. I'll then need to try umpteen times to simulate the situations where the engine has failed to start from hot shortly after shutting it down, in the hope that this alone has cured my problem. Fingers crossed...
Tony

PS For those that have changed the Crank Sensor, did you also replace the manifold gaskets or were they readily reusable, please?
 

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Discussion Starter · #25 ·
Hello Tony H,
Many thanks, but I believe what you say is only true for early North American cars. When you click on your link for no.27 (180137) in the detail it says "Quantity 2 four USA and CDN". However their thermostat housings are not the same. On the Europsares site they only show the later Thermostat (no.24 - 230890). However on the Scuderia site they show both versions - mine (230890) and the early North American version (230889) - which Scuderia note as "Valid for USA and CDN until engine 73454". I imagine that the second sensor screws into the housing of the 230889. Why on earth Maserati had two arrangements is anyone's guess !!!
Thanks again
Tony (P.)
 

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You're right, later cars have only one sensor. My guess is that the sensor on the thermostat housing might have run the cooling fans because it would measure temperature coming out of the radiator.

Something else to check is that the engine has been vented by opening the two bleed points.
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They are checking the function of the thermostat with the second coolant temp sensor to make sure it isn't stuck open...The ECU compares the temps between the two sensors...Jason
 

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Discussion Starter · #28 ·
You're right, later cars have only one sensor. My guess is that the sensor on the thermostat housing might have run the cooling fans because it would measure temperature coming out of the radiator.

Something else to check is that the engine has been vented by opening the two bleed points.
View attachment 140872
Thank you again Tony H.,
I had a major (70000 kms) service done in November, including changing the coolant and I got billed for 9 litres of coolant which sounds right. The garage I used services several Maserati 4200's so I'm hoping they knew to bleed the bleed points, but I will check to see if any air comes out when you open them. However if they hadn't used the bleed points what would happen? Could that cause my hot start problem?
Thanks again,
Tony
 

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Discussion Starter · #29 ·
They are checking the function of the thermostat with the second coolant temp sensor to make sure it isn't stuck open...The ECU compares the temps between the two sensors...Jason
Thank you for the explanation, Jason. Very clever arrangement. I wonder why they dropped it (and indeed never used it in Europe)? Saving a few dollars?
Thanks again,
Tony
 
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Thank you again Tony H.,
I had a major (70000 kms) service done in November, including changing the coolant and I got billed for 9 litres of coolant which sounds right. The garage I used services several Maserati 4200's so I'm hoping they knew to bleed the bleed points, but I will check to see if any air comes out when you open them. However if they hadn't used the bleed points what would happen? Could that cause my hot start problem?
Thanks again,
Tony
Thank you again Tony H.,
I had a major (70000 kms) service done in November, including changing the coolant and I got billed for 9 litres of coolant which sounds right. The garage I used services several Maserati 4200's so I'm hoping they knew to bleed the bleed points, but I will check to see if any air comes out when you open them. However if they hadn't used the bleed points what would happen? Could that cause my hot start problem?
Thanks again,
Tony
No, air in the cooling system will not cause that..I'm with the group here..Replace the crank sensor..Jason
 
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Discussion Starter · #31 ·
No, air in the cooling system will not cause that..I'm with the group here..Replace the crank sensor..Jason
Thanks again Jason,
I've now ordered a Crank Sensor, although I'm still hoping against hope that it's not that as it looks to be a real PITA to replace.
If I do end up replacing the Crank Sensor, do you think I will need also to replace the manifold gaskets or are they readily reusable, please?
Thanks
Tony
 

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Tony,

It's probably true that air in the system shouldn't cause hard starting. I mentioned the vents because I remembered it and air in the system can cause local overheating and engine damage so it's very important to do this right. Also, I recently changed my oil pressure sensor and if I had to so it again I'd put in a short extension. This would help to get it out in the future and, as you will find, you can't get the CPS out with the oil pressure sensor in place.
 

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Discussion Starter · #33 ·
Tony,

It's probably true that air in the system shouldn't cause hard starting. I mentioned the vents because I remembered it and air in the system can cause local overheating and engine damage so it's very important to do this right. Also, I recently changed my oil pressure sensor and if I had to so it again I'd put in a short extension. This would help to get it out in the future and, as you will find, you can't get the CPS out with the oil pressure sensor in place.
Yes, I've seen that I'd need to remove the oil pressure sensor to get at the CPS - that, and removing the whole inlet manifold, is why I'm "in denial" about changing the CPS ! Did you have (or make) a special tool to remove your oil pressure sensor?
 

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Yes, I've seen that I'd need to remove the oil pressure sensor to get at the CPS - that, and removing the whole inlet manifold, is why I'm "in denial" about changing the CPS ! Did you have (or make) a special tool to remove your oil pressure sensor?
Yes, I bought a crowfoot and then had to grind it much thinner to fit. The engine interferes with the fit and you can only get it on directly from the back. I did remove the manifold, which is quite easy, but when I put it back on the gasket folded and there was a gap on cylinder 5. You can't believe the chaos that ensued. I got a cylinder misfire code and the propeller shaft rattled like the TOB or bearings had disintegrated. Simple fix, once I found it, and the engine runs great again. I'd recommend changing the oil sensor while you're in there because it fails stuck on high pressure and your engine is totally at risk if you actually lose oil pressure.
 

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Discussion Starter · #35 ·
Yes, I bought a crowfoot and then had to grind it much thinner to fit. The engine interferes with the fit and you can only get it on directly from the back. I did remove the manifold, which is quite easy, but when I put it back on the gasket folded and there was a gap on cylinder 5. You can't believe the chaos that ensued. I got a cylinder misfire code and the propeller shaft rattled like the TOB or bearings had disintegrated. Simple fix, once I found it, and the engine runs great again. I'd recommend changing the oil sensor while you're in there because it fails stuck on high pressure and your engine is totally at risk if you actually lose oil pressure.
Thank you again Tony H,
As reported in my next posting, I fear I'm moving ever closer to replacing the Crank Sensor, so it looks as if the purchase a crowfoot will be coming soon. 24 mm I believe? But is there enough room to get one in?
 

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Discussion Starter · #36 ·
UPDATE : BAD NEWS
After testing my new Purge Valve vacuum retention and finding it to be better than my old one, I was quite optimistic about having solved my problem, and I would just have to do umpteen successful outings to prove it. Unfortunately today I had another fail to start when hot, so my work so far has been of no avail, except that I have eliminated the Purge Valve. I was also able to ensure that neither using my spare key nor locking and opening the door using the remote made any difference. I had my Launch set up to read engine revs, as suggested, but did not get "0" as a revs reading whilst trying to start the car. I did get some very unlikely readings though - 6848 and 8064... ...perhaps alternative signs of an iffy Crank Sensor? I did also try to sniff the exhaust pipes for the smell of petrol, but as I was on my own this was hard to achieve - there certainly was no strong smell of petrol by the time I lept out of the car and round to the back. As usual the car did eventually start and then drove perfectly.

I have ordered a new Crank Sensor but it is not due to arrive until next week.

Meanwhile I shall try replacing the Fuel Vapour Filter (220074, bought already) as it has never been replaced, just in case that is my problem. Watch this space...
 

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Thank you again Tony H,
As reported in my next posting, I fear I'm moving ever closer to replacing the Crank Sensor, so it looks as if the purchase a crowfoot will be coming soon. 24 mm I believe? But is there enough room to get one in?
You should get the pressure sensor first then you'll have the dimensions. I can't recall the size. As I said before it's a tight fit.

P.S. 24 mm
 
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