running issue
04-14-09, 08:22 PM
#1
10 pounds sounds so nasty
Thread Starter
Join Date: Sep 2006
Location: N.C.
Posts: 399
Likes: 0
Received 0 Likes
on
0 Posts
running issue
so i have tryed starting my seven over and over again, and its the same thing over and over. its seems i have a case of hot start with a fuel/air issue. the car has 550' prime and 720 secs could this be flooding my car out ? also it will start and when i go to give it gas its a very slow rev in rpm's as if the fuel isint spraying but it could also be from too much fuel going in at one time. the car hasent been tuned for the 720's i just put them in for compensation reasons. i have a set of 550s i can replace them with just haven't done it yet. so really what im asking here is how do you fix hot start and why would the car keep killing its self? i talked to another member on the forum about a problem he had that was along the same lines and he said that due to it being a fresh rebuild i need to prop open the afm and set my idle screw for 1500 to try and keep it alive i wont be able to try any of this till probably sat. but im just looking for options to get this thing going its been sitting far too long. another thing that happen is we worked on it all day yesterday with no start today we showed up charged the batt for a bit and turned the key car fired right then died.
04-14-09, 08:55 PM
#3
10 pounds sounds so nasty
Thread Starter
Join Date: Sep 2006
Location: N.C.
Posts: 399
Likes: 0
Received 0 Likes
on
0 Posts
even if the compression numbers are low once a initial start controling the throttle with my foot and flooring it when i see it dropping rpms should keep it alive.
04-15-09, 04:19 PM
#6
10 pounds sounds so nasty
Thread Starter
Join Date: Sep 2006
Location: N.C.
Posts: 399
Likes: 0
Received 0 Likes
on
0 Posts
04-15-09, 07:03 PM
#7
If this fresh rebuild has abnormally low compression, it's going to be hell to get it started & then keep it running under say 1k rpm. Go ahead and do whatever you can to boost the idle speed, but only a compression test will give you any useful information. Not all rebuilds turn out ok, so it's something you'll want to know.
Trending Topics
04-16-09, 09:28 AM
#10
10 pounds sounds so nasty
Thread Starter
Join Date: Sep 2006
Location: N.C.
Posts: 399
Likes: 0
Received 0 Likes
on
0 Posts
lol it gets pretty flooded somtimes also i got to thinking i probly need to try the MMO trick again just cause im sure the flooding thinned out the oil in the engine
04-16-09, 04:55 PM
#12
10 pounds sounds so nasty
Thread Starter
Join Date: Sep 2006
Location: N.C.
Posts: 399
Likes: 0
Received 0 Likes
on
0 Posts
once the key is relaxed from start to ON, if the engine is running then the fuel switch inside the afm is MADE, and the pump keeps on running. IF the switch in the afm is not MADE, then the pump stops once the key is not HELD to START anymore.
Simply jumpering the yellow, two socket fuel pump check connector overcomes the switch inside the afm and the pumps keeps running anytime the key is to ON or better.
04-16-09, 05:00 PM
#13
Just jump the fuel pump connector, and see if that helps. I don't know if it'll do anything. If you can put some miles on it, you'll at least get an indication of whether or not it will get better.
04-18-09, 04:36 PM
#17
10 pounds sounds so nasty
Thread Starter
Join Date: Sep 2006
Location: N.C.
Posts: 399
Likes: 0
Received 0 Likes
on
0 Posts
what ive been trying it hte method hailers told me hold foot ot floor to use the factory fuel cut and spray starter fluid to try and get it running and then once i have an initail start pat the gas to keep it alive but seems i cant keep it running is it just due to low comp ?
04-18-09, 07:22 PM
#18
Full Member
Join Date: Aug 2005
Location: Cairns, Australia
Posts: 83
Likes: 0
Received 0 Likes
on
0 Posts
30 on a FRESH REBUILD?
WOW! I'd be going to whoever did that rebuild and getting it done again, I'm fairly sure you have no chance of getting a car to start let alone run with numbers that low.
Are you sure you read the numbers right? I'm fairly sure you won't even get it started with numbers lower than about 60, and even at 60 or so it's VERY hard to start then.
WOW! I'd be going to whoever did that rebuild and getting it done again, I'm fairly sure you have no chance of getting a car to start let alone run with numbers that low.
Are you sure you read the numbers right? I'm fairly sure you won't even get it started with numbers lower than about 60, and even at 60 or so it's VERY hard to start then.
04-19-09, 11:51 AM
#19
10 pounds sounds so nasty
Thread Starter
Join Date: Sep 2006
Location: N.C.
Posts: 399
Likes: 0
Received 0 Likes
on
0 Posts
i was looking on rotary ress and he was saying that 30 was usually what was seen on fresh rebuilt engines with old housings and new seals, i knew my numbers were low hince the hard starting but then again i wasn't completely sure on how to use the gauge either.
04-19-09, 11:53 AM
#20
10 pounds sounds so nasty
Thread Starter
Join Date: Sep 2006
Location: N.C.
Posts: 399
Likes: 0
Received 0 Likes
on
0 Posts
Old parts have a certain amount of wear and tear on them. Mazda has specifications which account for this little bit of wear when deciding whether a part is re-useable or not. A used part that is within spec is not perfect, it's just close enough that it considered to be ok to use.
When a part starts to wear, it never wears perfectly evenly. Quality new parts are fabricated to within very tight spec. Usually any imperfection is so small that it is not noticable when you look at the part. However, when trying to compress ari/fuel the mix of wear on the used part and the imperfection on the new part may not make very good compression. This is because both parts will have slightly high and low parts when they press together to make a seal. Natually, the high parts will wear quickest and as they do more of the seal will actually touch what it is sealing to, which will equal better compression.
Exactly how long it takes a rebuild to fully build compression (the apex seals to seat) depends on the condition of the used housings and the kind of apex seal being used. Some will have good compression almost right away and some will take quite a while before they have good compression.
As for the hot start issue, I really don't know an explination as to why a rotary with low compression won't start while hot, but they do. I'm not sure if there is an exact number where someone can say for sure there will be a hot start issue or not, but I know when I got my car it had 90psi front and 60psi rear (thanks to 2 chipped apex seals and 2 cracked corner seals) and it would flood EVERYTIME I tried to start it with the engine hot. I don't have compressions number post rebuild, but I never had a hot start issue after the rebuild so I assume the compression is good.
90psi is a general number too. Exactly what condition an engine compressing to 90psi is in depends on the engine. A S5 N/A (9.7:1) that is compressing to 90psi is showing more wear than a S4 Turbo (8.4:1) (I think thoes compression ratios are right but i'm too lazy to look them up). Either way, compression will be lower than normally desireable. However some engines can last quite a while on 90psi.
When a part starts to wear, it never wears perfectly evenly. Quality new parts are fabricated to within very tight spec. Usually any imperfection is so small that it is not noticable when you look at the part. However, when trying to compress ari/fuel the mix of wear on the used part and the imperfection on the new part may not make very good compression. This is because both parts will have slightly high and low parts when they press together to make a seal. Natually, the high parts will wear quickest and as they do more of the seal will actually touch what it is sealing to, which will equal better compression.
Exactly how long it takes a rebuild to fully build compression (the apex seals to seat) depends on the condition of the used housings and the kind of apex seal being used. Some will have good compression almost right away and some will take quite a while before they have good compression.
As for the hot start issue, I really don't know an explination as to why a rotary with low compression won't start while hot, but they do. I'm not sure if there is an exact number where someone can say for sure there will be a hot start issue or not, but I know when I got my car it had 90psi front and 60psi rear (thanks to 2 chipped apex seals and 2 cracked corner seals) and it would flood EVERYTIME I tried to start it with the engine hot. I don't have compressions number post rebuild, but I never had a hot start issue after the rebuild so I assume the compression is good.
90psi is a general number too. Exactly what condition an engine compressing to 90psi is in depends on the engine. A S5 N/A (9.7:1) that is compressing to 90psi is showing more wear than a S4 Turbo (8.4:1) (I think thoes compression ratios are right but i'm too lazy to look them up). Either way, compression will be lower than normally desireable. However some engines can last quite a while on 90psi.
04-19-09, 11:57 AM
#21
10 pounds sounds so nasty
Thread Starter
Join Date: Sep 2006
Location: N.C.
Posts: 399
Likes: 0
Received 0 Likes
on
0 Posts
also i have sat down and read some thing in the searche's i have been doing
so i always start my car with gas foot floored
spray some starter fluid in the TB
and try cranking car will somtimes kick over, then as soon as it turns i give it some gas and it will run and show RPM's a lil swoosh from the BOV and then it will start to fall and i'll floor the gas to try and keep it alive then dies, and wont start again. somthing point ot injectors others to compression i just dont understand why when i try to give it gas it dies. if i could figure that out the car would run.
so i always start my car with gas foot floored
spray some starter fluid in the TB
and try cranking car will somtimes kick over, then as soon as it turns i give it some gas and it will run and show RPM's a lil swoosh from the BOV and then it will start to fall and i'll floor the gas to try and keep it alive then dies, and wont start again. somthing point ot injectors others to compression i just dont understand why when i try to give it gas it dies. if i could figure that out the car would run.
04-19-09, 04:31 PM
#23
10 pounds sounds so nasty
Thread Starter
Join Date: Sep 2006
Location: N.C.
Posts: 399
Likes: 0
Received 0 Likes
on
0 Posts
see thats the thing
lol see thats just it, i can get it to start its running part im baffled on she only wants to run a few seconds before it dies and then i have a pain trying to get it fired back up and if i do same thing again. it will start run for a few seconds with me patting the gas then when she starts to go down in RPM's i floor it to try and keep it going then dies.
04-19-09, 08:51 PM
#24
Retired Moderator, RIP
iTrader: (142)
Join Date: Sep 2005
Location: Smiths Falls.(near Ottawa!.Mapquest IT!)
Posts: 25,581
Likes: 0
Received 131 Likes
on
114 Posts
Is your AFM plugged in?..if not,it will start and die,like you are Saying it does when you try to start it.
I am thinking you disconnected the AFM to get at the intake with quickstart fluid(Ether).
I am thinking you disconnected the AFM to get at the intake with quickstart fluid(Ether).
04-19-09, 09:15 PM
#25
10 pounds sounds so nasty
Thread Starter
Join Date: Sep 2006
Location: N.C.
Posts: 399
Likes: 0
Received 0 Likes
on
0 Posts
thatsthe first thing we looked at but its plugged in and the right way as well we're ganna try to do somthings with it tomorrow and see how that goes.